#3734 Refactor and convert CategoryPresenter to kotlin (#3735)

app/src/main/java/fr/free/nrw/commons/category/CategoriesModel.java

@@ -1,242 +0,0 @@
-package fr.free.nrw.commons.category;
-
-import android.text.TextUtils;
-import fr.free.nrw.commons.kvstore.JsonKvStore;
-import fr.free.nrw.commons.upload.GpsCategoryModel;
-import fr.free.nrw.commons.utils.StringSortingUtils;
-import io.reactivex.Observable;
-import java.util.ArrayList;
-import java.util.Calendar;
-import java.util.Comparator;
-import java.util.Date;
-import java.util.List;
-import javax.inject.Inject;
-import javax.inject.Named;
-import timber.log.Timber;
-
-/**
- * The model class for categories in upload
- */
-public class CategoriesModel{
-    private static final int SEARCH_CATS_LIMIT = 25;
-
-    private final CategoryClient categoryClient;
-    private final CategoryDao categoryDao;
-    private final JsonKvStore directKvStore;
-    private final GpsCategoryModel gpsCategoryModel;
-
-    private List<CategoryItem> selectedCategories;
-
-    @Inject
-    public CategoriesModel(CategoryClient categoryClient,
-        CategoryDao categoryDao,
-        @Named("default_preferences") JsonKvStore directKvStore,
-        final GpsCategoryModel gpsCategoryModel) {
-        this.categoryClient = categoryClient;
-        this.categoryDao = categoryDao;
-        this.directKvStore = directKvStore;
-        this.gpsCategoryModel = gpsCategoryModel;
-        this.selectedCategories = new ArrayList<>();
-    }
-
-    /**
-     * Sorts CategoryItem by similarity
-     * @param filter
-     * @return
-     */
-    public Comparator<CategoryItem> sortBySimilarity(final String filter) {
-        Comparator<String> stringSimilarityComparator = StringSortingUtils.sortBySimilarity(filter);
-        return (firstItem, secondItem) -> stringSimilarityComparator
-                .compare(firstItem.getName(), secondItem.getName());
-    }
-
-    /**
-     * Returns if the item contains an year
-     * @param item
-     * @return
-     */
-    public boolean containsYear(String item) {
-        //Check for current and previous year to exclude these categories from removal
-        Calendar now = Calendar.getInstance();
-        int year = now.get(Calendar.YEAR);
-        String yearInString = String.valueOf(year);
-
-        int prevYear = year - 1;
-        String prevYearInString = String.valueOf(prevYear);
-        Timber.d("Previous year: %s", prevYearInString);
-
-        //Check if item contains a 4-digit word anywhere within the string (.* is wildcard)
-        //And that item does not equal the current year or previous year
-        //And if it is an irrelevant category such as Media_needing_categories_as_of_16_June_2017(Issue #750)
-        //Check if the year in the form of XX(X)0s is relevant, i.e. in the 2000s or 2010s as stated in Issue #1029
-        return ((item.matches(".*(19|20)\\d{2}.*") && !item.contains(yearInString) && !item.contains(prevYearInString))
-                || item.matches("(.*)needing(.*)") || item.matches("(.*)taken on(.*)")
-                || (item.matches(".*0s.*") && !item.matches(".*(200|201)0s.*")));
-    }
-
-    /**
-     * Updates category count in category dao
-     * @param item
-     */
-    public void updateCategoryCount(CategoryItem item) {
-        Category category = categoryDao.find(item.getName());
-
-        // Newly used category...
-        if (category == null) {
-            category = new Category(null, item.getName(), new Date(), 0);
-        }
-
-        category.incTimesUsed();
-        categoryDao.save(category);
-    }
-
-
-    /**
-     * Regional category search
-     * @param term
-     * @param imageTitleList
-     * @return
-     */
-    public Observable<CategoryItem> searchAll(String term, List<String> imageTitleList) {
-        //If query text is empty, show him category based on gps and title and recent searches
-        if (TextUtils.isEmpty(term)) {
-            Observable<CategoryItem> categoryItemObservable =
-                Observable.concat(gpsCategories(), titleCategories(imageTitleList));
-            if (hasDirectCategories()) {
-                return Observable.concat(
-                    categoryItemObservable,
-                    directCategories(),
-                    recentCategories()
-                );
-            }
-            return categoryItemObservable;
-        }
-
-        //otherwise, search API for matching categories
-        //term passed as lower case to make search case-insensitive(taking only lower case for everything)
-        return categoryClient
-                .searchCategoriesForPrefix(term.toLowerCase(), SEARCH_CATS_LIMIT)
-                .map(name -> new CategoryItem(name, false));
-    }
-
-
-    /**
-     * Returns if we have a category in DirectKV Store
-     * @return
-     */
-    private boolean hasDirectCategories() {
-        return !directKvStore.getString("Category", "").equals("");
-    }
-
-    /**
-     * Returns categories in DirectKVStore
-     * @return
-     */
-    private Observable<CategoryItem> directCategories() {
-        String directCategory = directKvStore.getString("Category", "");
-        List<String> categoryList = new ArrayList<>();
-        Timber.d("Direct category found: " + directCategory);
-
-        if (!directCategory.equals("")) {
-            categoryList.add(directCategory);
-            Timber.d("DirectCat does not equal emptyString. Direct Cat list has " + categoryList);
-        }
-        return Observable.fromIterable(categoryList).map(name -> new CategoryItem(name, false));
-    }
-
-    /**
-     * Returns GPS categories
-     * @return
-     */
-    Observable<CategoryItem> gpsCategories() {
-        return Observable.fromIterable(gpsCategoryModel.getCategoryList())
-                .map(name -> new CategoryItem(name, false));
-    }
-
-    /**
-     * Returns title based categories
-     * @param titleList
-     * @return
-     */
-    private Observable<CategoryItem> titleCategories(List<String> titleList) {
-        return Observable.fromIterable(titleList)
-                .concatMap(this::getTitleCategories);
-    }
-
-    /**
-     * Return category for single title
-     * title is converted to lower case to make search case-insensitive
-     * @param title
-     * @return
-     */
-    private Observable<CategoryItem> getTitleCategories(String title) {
-        return categoryClient.searchCategories(title.toLowerCase(), SEARCH_CATS_LIMIT)
-                .map(name -> new CategoryItem(name, false));
-    }
-
-    /**
-     * Returns recent categories
-     * @return
-     */
-    private Observable<CategoryItem> recentCategories() {
-        return Observable.fromIterable(categoryDao.recentCategories(SEARCH_CATS_LIMIT))
-                .map(s -> new CategoryItem(s, false));
-    }
-
-    /**
-     * Handles category item selection
-     * @param item
-     */
-    public void onCategoryItemClicked(CategoryItem item) {
-        if (item.isSelected()) {
-            selectCategory(item);
-            updateCategoryCount(item);
-        } else {
-            unselectCategory(item);
-        }
-    }
-
-    /**
-     * Select's category
-     * @param item
-     */
-    public void selectCategory(CategoryItem item) {
-        selectedCategories.add(item);
-    }
-
-    /**
-     * Unselect Category
-     * @param item
-     */
-    public void unselectCategory(CategoryItem item) {
-        selectedCategories.remove(item);
-    }
-
-
-    /**
-     * Get Selected Categories
-     * @return
-     */
-    public List<CategoryItem> getSelectedCategories() {
-        return selectedCategories;
-    }
-
-    /**
-     * Get Categories String List
-     * @return
-     */
-    public List<String> getCategoryStringList() {
-        List<String> output = new ArrayList<>();
-        for (CategoryItem item : selectedCategories) {
-            output.add(item.getName());
-        }
-        return output;
-    }
-
-    /**
-     * Cleanup the existing in memory cache's
-     */
-    public void cleanUp() {
-        this.selectedCategories.clear();
-    }
-}

app/src/main/java/fr/free/nrw/commons/category/CategoriesModel.kt

@@ -0,0 +1,152 @@
+package fr.free.nrw.commons.category
+
+import android.text.TextUtils
+import fr.free.nrw.commons.upload.GpsCategoryModel
+import fr.free.nrw.commons.utils.StringSortingUtils
+import io.reactivex.Observable
+import io.reactivex.functions.Function3
+import timber.log.Timber
+import java.util.*
+import javax.inject.Inject
+
+/**
+ * The model class for categories in upload
+ */
+class CategoriesModel @Inject constructor(
+    private val categoryClient: CategoryClient,
+    private val categoryDao: CategoryDao,
+    private val gpsCategoryModel: GpsCategoryModel
+) {
+    private val selectedCategories: MutableList<CategoryItem> = mutableListOf()
+
+    /**
+     * Returns if the item contains an year
+     * @param item
+     * @return
+     */
+    fun containsYear(item: String): Boolean {
+        //Check for current and previous year to exclude these categories from removal
+        val now = Calendar.getInstance()
+        val year = now[Calendar.YEAR]
+        val yearInString = year.toString()
+        val prevYear = year - 1
+        val prevYearInString = prevYear.toString()
+        Timber.d("Previous year: %s", prevYearInString)
+
+        //Check if item contains a 4-digit word anywhere within the string (.* is wildcard)
+        //And that item does not equal the current year or previous year
+        //And if it is an irrelevant category such as Media_needing_categories_as_of_16_June_2017(Issue #750)
+        //Check if the year in the form of XX(X)0s is relevant, i.e. in the 2000s or 2010s as stated in Issue #1029
+        return item.matches(".*(19|20)\\d{2}.*".toRegex())
+                && !item.contains(yearInString)
+                && !item.contains(prevYearInString)
+                || item.matches("(.*)needing(.*)".toRegex())
+                || item.matches("(.*)taken on(.*)".toRegex())
+                || item.matches(".*0s.*".toRegex())
+                && !item.matches(".*(200|201)0s.*".toRegex())
+    }
+
+    /**
+     * Updates category count in category dao
+     * @param item
+     */
+    fun updateCategoryCount(item: CategoryItem) {
+        var category = categoryDao.find(item.name)
+
+        // Newly used category...
+        if (category == null) {
+            category = Category(null, item.name, Date(), 0)
+        }
+        category.incTimesUsed()
+        categoryDao.save(category)
+    }
+
+    /**
+     * Regional category search
+     * @param term
+     * @param imageTitleList
+     * @return
+     */
+    fun searchAll(term: String, imageTitleList: List<String>): Observable<List<CategoryItem>> {
+        return suggestionsOrSearch(term, imageTitleList)
+            .map { it.map { CategoryItem(it, false) } }
+    }
+
+    private fun suggestionsOrSearch(term: String, imageTitleList: List<String>):
+            Observable<List<String>> {
+        return if (TextUtils.isEmpty(term))
+            Observable.combineLatest(
+                gpsCategoryModel.categoriesFromLocation,
+                titleCategories(imageTitleList),
+                Observable.just(categoryDao.recentCategories(SEARCH_CATS_LIMIT)),
+                Function3(::combine)
+            )
+        else
+            categoryClient.searchCategoriesForPrefix(term.toLowerCase(), SEARCH_CATS_LIMIT)
+                .map { it.sortedWith(StringSortingUtils.sortBySimilarity(term)) }
+    }
+
+    private fun combine(
+        locationCategories: List<String>,
+        titles: List<String>,
+        recents: List<String>
+    ) = locationCategories + titles + recents
+
+
+    /**
+     * Returns title based categories
+     * @param titleList
+     * @return
+     */
+    private fun titleCategories(titleList: List<String>): Observable<List<String>> {
+        return if (titleList.isNotEmpty())
+            Observable.combineLatest(titleList.map { getTitleCategories(it) }) { searchResults ->
+                searchResults.map { it as List<String> }.flatten()
+            }
+        else
+            Observable.just(emptyList())
+    }
+
+    /**
+     * Return category for single title
+     * title is converted to lower case to make search case-insensitive
+     * @param title
+     * @return
+     */
+    private fun getTitleCategories(title: String): Observable<List<String>> {
+        return categoryClient.searchCategories(title.toLowerCase(), SEARCH_CATS_LIMIT)
+    }
+
+
+    /**
+     * Handles category item selection
+     * @param item
+     */
+    fun onCategoryItemClicked(item: CategoryItem) {
+        if (item.isSelected) {
+            selectedCategories.add(item)
+            updateCategoryCount(item)
+        } else {
+            selectedCategories.remove(item)
+        }
+    }
+
+    /**
+     * Get Selected Categories
+     * @return
+     */
+    fun getSelectedCategories(): List<CategoryItem> {
+        return selectedCategories
+    }
+
+    /**
+     * Cleanup the existing in memory cache's
+     */
+    fun cleanUp() {
+        selectedCategories.clear()
+    }
+
+    companion object {
+        private const val SEARCH_CATS_LIMIT = 25
+    }
+}

app/src/main/java/fr/free/nrw/commons/category/CategoryClient.java

@@ -1,125 +0,0 @@
-package fr.free.nrw.commons.category;
-
-
-import androidx.annotation.NonNull;
-
-import org.wikipedia.dataclient.mwapi.MwQueryPage;
-import org.wikipedia.dataclient.mwapi.MwQueryResponse;
-import org.wikipedia.dataclient.mwapi.MwQueryResult;
-
-import java.util.List;
-
-import javax.inject.Inject;
-import javax.inject.Singleton;
-
-import io.reactivex.Observable;
-import timber.log.Timber;
-
-/**
- * Category Client to handle custom calls to Commons MediaWiki APIs
- */
-@Singleton
-public class CategoryClient {
-
-    private final CategoryInterface CategoryInterface;
-
-    @Inject
-    public CategoryClient(CategoryInterface CategoryInterface) {
-        this.CategoryInterface = CategoryInterface;
-    }
-
-    /**
-     * Searches for categories containing the specified string.
-     *
-     * @param filter    The string to be searched
-     * @param itemLimit How many results are returned
-     * @param offset    Starts returning items from the nth result. If offset is 9, the response starts with the 9th item of the search result
-     * @return
-     */
-    public Observable<String> searchCategories(String filter, int itemLimit, int offset) {
-        return responseToCategoryName(CategoryInterface.searchCategories(filter, itemLimit, offset));
-
-    }
-
-    /**
-     * Searches for categories containing the specified string.
-     *
-     * @param filter    The string to be searched
-     * @param itemLimit How many results are returned
-     * @return
-     */
-    public Observable<String> searchCategories(String filter, int itemLimit) {
-        return searchCategories(filter, itemLimit, 0);
-
-    }
-
-    /**
-     * Searches for categories starting with the specified string.
-     * 
-     * @param prefix    The prefix to be searched
-     * @param itemLimit How many results are returned
-     * @param offset    Starts returning items from the nth result. If offset is 9, the response starts with the 9th item of the search result
-     * @return
-     */
-    public Observable<String> searchCategoriesForPrefix(String prefix, int itemLimit, int offset) {
-        return responseToCategoryName(CategoryInterface.searchCategoriesForPrefix(prefix, itemLimit, offset));
-    }
-
-    /**
-     * Searches for categories starting with the specified string.
-     *
-     * @param prefix    The prefix to be searched
-     * @param itemLimit How many results are returned
-     * @return
-     */
-    public Observable<String> searchCategoriesForPrefix(String prefix, int itemLimit) {
-        return searchCategoriesForPrefix(prefix, itemLimit, 0);
-    }
-
-
-    /**
-     * The method takes categoryName as input and returns a List of Subcategories
-     * It uses the generator query API to get the subcategories in a category, 500 at a time.
-     *
-     * @param categoryName Category name as defined on commons
-     * @return Observable emitting the categories returned. If our search yielded "Category:Test", "Test" is emitted.
-     */
-    public Observable<String> getSubCategoryList(String categoryName) {
-        return responseToCategoryName(CategoryInterface.getSubCategoryList(categoryName));
-    }
-
-    /**
-     * The method takes categoryName as input and returns a List of parent categories
-     * It uses the generator query API to get the parent categories of a category, 500 at a time.
-     *
-     * @param categoryName Category name as defined on commons
-     * @return
-     */
-    @NonNull
-    public Observable<String> getParentCategoryList(String categoryName) {
-        return responseToCategoryName(CategoryInterface.getParentCategoryList(categoryName));
-    }
-
-    /**
-     * Internal function to reduce code reuse. Extracts the categories returned from MwQueryResponse.
-     *
-     * @param responseObservable The query response observable
-     * @return Observable emitting the categories returned. If our search yielded "Category:Test", "Test" is emitted.
-     */
-    private Observable<String> responseToCategoryName(Observable<MwQueryResponse> responseObservable) {
-        return responseObservable
-                .flatMap(mwQueryResponse -> {
-                    MwQueryResult query;
-                    List<MwQueryPage> pages;
-                    if ((query = mwQueryResponse.query()) == null ||
-                            (pages = query.pages()) == null) {
-                        Timber.d("No categories returned.");
-                        return Observable.empty();
-                    } else
-                        return Observable.fromIterable(pages);
-                })
-                .map(MwQueryPage::title)
-                .doOnEach(s -> Timber.d("Category returned: %s", s))
-                .map(cat -> cat.replace("Category:", ""));
-    }
-}

app/src/main/java/fr/free/nrw/commons/category/CategoryClient.kt

@@ -0,0 +1,79 @@
+package fr.free.nrw.commons.category
+
+import io.reactivex.Observable
+import org.wikipedia.dataclient.mwapi.MwQueryResponse
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * Category Client to handle custom calls to Commons MediaWiki APIs
+ */
+@Singleton
+class CategoryClient @Inject constructor(private val categoryInterface: CategoryInterface) {
+    /**
+     * Searches for categories containing the specified string.
+     *
+     * @param filter    The string to be searched
+     * @param itemLimit How many results are returned
+     * @param offset    Starts returning items from the nth result. If offset is 9, the response starts with the 9th item of the search result
+     * @return
+     */
+    @JvmOverloads
+    fun searchCategories(filter: String?, itemLimit: Int, offset: Int = 0):
+            Observable<List<String>> {
+        return responseToCategoryName(categoryInterface.searchCategories(filter, itemLimit, offset))
+    }
+
+    /**
+     * Searches for categories starting with the specified string.
+     *
+     * @param prefix    The prefix to be searched
+     * @param itemLimit How many results are returned
+     * @param offset    Starts returning items from the nth result. If offset is 9, the response starts with the 9th item of the search result
+     * @return
+     */
+    @JvmOverloads
+    fun searchCategoriesForPrefix(prefix: String?, itemLimit: Int, offset: Int = 0):
+            Observable<List<String>> {
+        return responseToCategoryName(
+            categoryInterface.searchCategoriesForPrefix(prefix, itemLimit, offset)
+        )
+    }
+
+    /**
+     * The method takes categoryName as input and returns a List of Subcategories
+     * It uses the generator query API to get the subcategories in a category, 500 at a time.
+     *
+     * @param categoryName Category name as defined on commons
+     * @return Observable emitting the categories returned. If our search yielded "Category:Test", "Test" is emitted.
+     */
+    fun getSubCategoryList(categoryName: String?): Observable<List<String>> {
+        return responseToCategoryName(categoryInterface.getSubCategoryList(categoryName))
+    }
+
+    /**
+     * The method takes categoryName as input and returns a List of parent categories
+     * It uses the generator query API to get the parent categories of a category, 500 at a time.
+     *
+     * @param categoryName Category name as defined on commons
+     * @return
+     */
+    fun getParentCategoryList(categoryName: String?): Observable<List<String>> {
+        return responseToCategoryName(categoryInterface.getParentCategoryList(categoryName))
+    }
+
+    /**
+     * Internal function to reduce code reuse. Extracts the categories returned from MwQueryResponse.
+     *
+     * @param responseObservable The query response observable
+     * @return Observable emitting the categories returned. If our search yielded "Category:Test", "Test" is emitted.
+     */
+    private fun responseToCategoryName(responseObservable: Observable<MwQueryResponse>): Observable<List<String>> {
+        return responseObservable
+            .map { it.query()?.pages() ?: emptyList() }
+            .map {
+                it.map { page -> page.title().replace("Category:", "") }
+            }
+    }
+
+}

app/src/main/java/fr/free/nrw/commons/category/CategoryItem.java

@@ -1,79 +0,0 @@
-package fr.free.nrw.commons.category;
-
-import android.os.Parcel;
-import android.os.Parcelable;
-
-public class CategoryItem implements Parcelable {
-    private final String name;
-    private boolean selected;
-
-    public static Creator<CategoryItem> CREATOR = new Creator<CategoryItem>() {
-        @Override
-        public CategoryItem createFromParcel(Parcel parcel) {
-            return new CategoryItem(parcel);
-        }
-
-        @Override
-        public CategoryItem[] newArray(int i) {
-            return new CategoryItem[0];
-        }
-    };
-
-    public CategoryItem(String name, boolean selected) {
-        this.name = name;
-        this.selected = selected;
-    }
-
-    private CategoryItem(Parcel in) {
-        name = in.readString();
-        selected = in.readInt() == 1;
-    }
-
-    public String getName() {
-        return name;
-    }
-
-    public boolean isSelected() {
-        return selected;
-    }
-
-    public void setSelected(boolean selected) {
-        this.selected = selected;
-    }
-
-    @Override
-    public int describeContents() {
-        return 0;
-    }
-
-    @Override
-    public void writeToParcel(Parcel parcel, int flags) {
-        parcel.writeString(name);
-        parcel.writeInt(selected ? 1 : 0);
-    }
-
-    @Override
-    public boolean equals(Object o) {
-        if (this == o) {
-            return true;
-        }
-        if (o == null || getClass() != o.getClass()) {
-            return false;
-        }
-
-        CategoryItem that = (CategoryItem) o;
-
-        return name.equals(that.name);
-
-    }
-
-    @Override
-    public int hashCode() {
-        return name.hashCode();
-    }
-
-    @Override
-    public String toString() {
-        return "CategoryItem: '" + name + '\'';
-    }
-}

app/src/main/java/fr/free/nrw/commons/category/CategoryItem.kt

@@ -0,0 +1,27 @@
+package fr.free.nrw.commons.category
+
+import android.os.Parcelable
+import kotlinx.android.parcel.Parcelize
+
+@Parcelize
+data class CategoryItem(val name: String, var isSelected: Boolean) : Parcelable {
+
+    override fun toString(): String {
+        return "CategoryItem: '$name'"
+    }
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (javaClass != other?.javaClass) return false
+
+        other as CategoryItem
+
+        if (name != other.name) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        return name.hashCode()
+    }
+}

app/src/main/java/fr/free/nrw/commons/category/SubCategoryListFragment.java

@@ -91,13 +91,11 @@ public class SubCategoryListFragment extends CommonsDaggerSupportFragment {
             compositeDisposable.add(categoryClient.getParentCategoryList("Category:"+categoryName)
                     .subscribeOn(Schedulers.io())
                     .observeOn(AndroidSchedulers.mainThread())
-                    .collect(ArrayList<String>::new, ArrayList::add)
                     .subscribe(this::handleSuccess, this::handleError));
         } else {
             compositeDisposable.add(categoryClient.getSubCategoryList("Category:"+categoryName)
                     .subscribeOn(Schedulers.io())
                     .observeOn(AndroidSchedulers.mainThread())
-                    .collect(ArrayList<String>::new, ArrayList::add)
                     .subscribe(this::handleSuccess, this::handleError));
         }
     }

app/src/main/java/fr/free/nrw/commons/explore/categories/SearchCategoryFragment.java

@@ -133,7 +133,6 @@ public class SearchCategoryFragment extends CommonsDaggerSupportFragment {
                 .subscribeOn(Schedulers.io())
                 .observeOn(AndroidSchedulers.mainThread())
                 .doOnSubscribe(disposable -> saveQuery(query))
-                .collect(ArrayList<String>::new, ArrayList::add)
                 .subscribe(this::handleSuccess, this::handleError));
     }
 
@@ -150,7 +149,6 @@ public class SearchCategoryFragment extends CommonsDaggerSupportFragment {
         compositeDisposable.add(categoryClient.searchCategories(query,25, queryList.size())
                 .subscribeOn(Schedulers.io())
                 .observeOn(AndroidSchedulers.mainThread())
-                .collect(ArrayList<String>::new, ArrayList::add)
                 .subscribe(this::handlePaginationSuccess, this::handleError));
     }
 

app/src/main/java/fr/free/nrw/commons/repository/UploadRepository.java

@@ -18,7 +18,6 @@ import io.reactivex.Flowable;
 import io.reactivex.Observable;
 import io.reactivex.Single;
 import java.io.IOException;
-import java.util.Comparator;
 import java.util.List;
 import java.util.Locale;
 import javax.inject.Inject;
@@ -111,20 +110,10 @@ public class UploadRepository {
      * @param imageTitleList
      * @return
      */
-    public Observable<CategoryItem> searchAll(String query, List<String> imageTitleList) {
+    public Observable<List<CategoryItem>> searchAll(String query, List<String> imageTitleList) {
         return categoriesModel.searchAll(query, imageTitleList);
     }
 
-    /**
-     * returns the string list of categories
-     *
-     * @return
-     */
-
-    public List<String> getCategoryStringList() {
-        return categoriesModel.getCategoryStringList();
-    }
-
     /**
      * sets the list of selected categories for the current upload
      *
@@ -143,16 +132,6 @@ public class UploadRepository {
         categoriesModel.onCategoryItemClicked(categoryItem);
     }
 
-    /**
-     * returns category sorted based on similarity with query
-     *
-     * @param query
-     * @return
-     */
-    public Comparator<? super CategoryItem> sortBySimilarity(String query) {
-        return categoriesModel.sortBySimilarity(query);
-    }
-
     /**
      * prunes the category list for irrelevant categories see #750
      *

app/src/main/java/fr/free/nrw/commons/upload/FileProcessor.kt

@@ -180,7 +180,7 @@ class FileProcessor @Inject constructor(
                 .subscribeOn(Schedulers.io())
                 .observeOn(Schedulers.io())
                 .subscribe(
-                    { gpsCategoryModel.categoryList = it },
+                    gpsCategoryModel::setCategoriesFromLocation,
                     {
                         Timber.e(it)
                         gpsCategoryModel.clear()

app/src/main/java/fr/free/nrw/commons/upload/GpsCategoryModel.java

@@ -1,36 +0,0 @@
-package fr.free.nrw.commons.upload;
-
-import java.util.ArrayList;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
-
-import javax.inject.Inject;
-import javax.inject.Singleton;
-
-@Singleton
-public class GpsCategoryModel {
-    private Set<String> categorySet;
-
-    @Inject
-    public GpsCategoryModel() {
-        clear();
-    }
-
-    public void clear() {
-        categorySet = new HashSet<>();
-    }
-
-    public boolean getGpsCatExists() {
-        return !categorySet.isEmpty();
-    }
-
-    public List<String> getCategoryList() {
-        return new ArrayList<>(categorySet);
-    }
-
-    public void setCategoryList(List<String> categoryList) {
-        clear();
-        categorySet.addAll(categoryList != null ? categoryList : new ArrayList<>());
-    }
-}

app/src/main/java/fr/free/nrw/commons/upload/GpsCategoryModel.kt

@@ -0,0 +1,18 @@
+package fr.free.nrw.commons.upload
+
+import io.reactivex.subjects.BehaviorSubject
+import javax.inject.Inject
+import javax.inject.Singleton
+
+@Singleton
+class GpsCategoryModel @Inject constructor() {
+    val categoriesFromLocation = BehaviorSubject.createDefault(emptyList<String>())
+
+    fun clear() {
+        categoriesFromLocation.onNext(emptyList())
+    }
+
+    fun setCategoriesFromLocation(categoryList: List<String>) {
+        categoriesFromLocation.onNext(categoryList)
+    }
+}

app/src/main/java/fr/free/nrw/commons/upload/UploadActivity.java

@@ -30,7 +30,6 @@ import fr.free.nrw.commons.CommonsApplication;
 import fr.free.nrw.commons.R;
 import fr.free.nrw.commons.auth.LoginActivity;
 import fr.free.nrw.commons.auth.SessionManager;
-import fr.free.nrw.commons.category.CategoriesModel;
 import fr.free.nrw.commons.contributions.ContributionController;
 import fr.free.nrw.commons.filepicker.UploadableFile;
 import fr.free.nrw.commons.kvstore.JsonKvStore;
@@ -63,8 +62,6 @@ public class UploadActivity extends BaseActivity implements UploadContract.View,
     @Inject
     UploadContract.UserActionListener presenter;
     @Inject
-    CategoriesModel categoriesModel;
-    @Inject
     SessionManager sessionManager;
     @Inject
     UserClient userClient;
@@ -96,7 +93,7 @@ public class UploadActivity extends BaseActivity implements UploadContract.View,
     private CompositeDisposable compositeDisposable;
     private ProgressDialog progressDialog;
     private UploadImageAdapter uploadImagesAdapter;
-    private List<Fragment> fragments;
+    private List<UploadBaseFragment> fragments;
     private UploadCategoriesFragment uploadCategoriesFragment;
     private DepictsFragment depictsFragment;
     private MediaLicenseFragment mediaLicenseFragment;
@@ -416,6 +413,7 @@ public class UploadActivity extends BaseActivity implements UploadContract.View,
     public void onNextButtonClicked(int index) {
         if (index < fragments.size() - 1) {
             vpUpload.setCurrentItem(index + 1, false);
+            fragments.get(index + 1).onBecameVisible();
         } else {
             presenter.handleSubmit();
         }
@@ -425,6 +423,7 @@ public class UploadActivity extends BaseActivity implements UploadContract.View,
     public void onPreviousButtonClicked(int index) {
         if (index != 0) {
             vpUpload.setCurrentItem(index - 1, true);
+            fragments.get(index - 1).onBecameVisible();
         }
     }
 
@@ -433,14 +432,14 @@ public class UploadActivity extends BaseActivity implements UploadContract.View,
      */
 
     private class UploadImageAdapter extends FragmentStatePagerAdapter {
-        List<Fragment> fragments;
+        List<UploadBaseFragment> fragments;
 
         public UploadImageAdapter(FragmentManager fragmentManager) {
             super(fragmentManager);
             this.fragments = new ArrayList<>();
         }
 
-        public void setFragments(List<Fragment> fragments) {
+        public void setFragments(List<UploadBaseFragment> fragments) {
             this.fragments = fragments;
             notifyDataSetChanged();
         }

app/src/main/java/fr/free/nrw/commons/upload/UploadBaseFragment.java

@@ -22,6 +22,9 @@ public class UploadBaseFragment extends CommonsDaggerSupportFragment {
         this.callback = callback;
     }
 
+    protected void onBecameVisible() {
+    }
+
     public interface Callback {
 
         void onNextButtonClicked(int index);

app/src/main/java/fr/free/nrw/commons/upload/UploadModule.java

@@ -22,8 +22,8 @@ public abstract class UploadModule {
                                                                                 presenter);
 
     @Binds
-    public abstract CategoriesContract.UserActionListener bindsCategoriesPresenter(CategoriesPresenter
+    public abstract CategoriesContract.UserActionListener bindsCategoriesPresenter(
-                                                                                           presenter);
+        CategoriesPresenter presenter);
 
     @Binds
     public abstract MediaLicenseContract.UserActionListener bindsMediaLicensePresenter(

app/src/main/java/fr/free/nrw/commons/upload/categories/CategoriesPresenter.java

@@ -1,146 +0,0 @@
-package fr.free.nrw.commons.upload.categories;
-
-import static fr.free.nrw.commons.di.CommonsApplicationModule.IO_THREAD;
-import static fr.free.nrw.commons.di.CommonsApplicationModule.MAIN_THREAD;
-
-import android.text.TextUtils;
-import fr.free.nrw.commons.R;
-import fr.free.nrw.commons.category.CategoryItem;
-import fr.free.nrw.commons.repository.UploadRepository;
-import fr.free.nrw.commons.upload.UploadItem;
-import io.reactivex.Observable;
-import io.reactivex.Scheduler;
-import io.reactivex.disposables.CompositeDisposable;
-import io.reactivex.disposables.Disposable;
-import java.lang.reflect.Proxy;
-import java.util.ArrayList;
-import java.util.List;
-import javax.inject.Inject;
-import javax.inject.Named;
-import javax.inject.Singleton;
-import timber.log.Timber;
-
-/**
- * The presenter class for UploadCategoriesFragment
- */
-@Singleton
-public class CategoriesPresenter implements CategoriesContract.UserActionListener {
-
-    private static final CategoriesContract.View DUMMY = (CategoriesContract.View) Proxy
-            .newProxyInstance(
-                    CategoriesContract.View.class.getClassLoader(),
-                    new Class[]{CategoriesContract.View.class},
-                    (proxy, method, methodArgs) -> null);
-    private final Scheduler ioScheduler;
-    private final Scheduler mainThreadScheduler;
-
-    CategoriesContract.View view = DUMMY;
-    private UploadRepository repository;
-
-    private CompositeDisposable compositeDisposable;
-
-    @Inject
-    public CategoriesPresenter(UploadRepository repository, @Named(IO_THREAD) Scheduler ioScheduler,
-                               @Named(MAIN_THREAD) Scheduler mainThreadScheduler) {
-        this.repository = repository;
-        this.ioScheduler = ioScheduler;
-        this.mainThreadScheduler = mainThreadScheduler;
-        compositeDisposable = new CompositeDisposable();
-    }
-
-    @Override
-    public void onAttachView(CategoriesContract.View view) {
-        this.view = view;
-    }
-
-    @Override
-    public void onDetachView() {
-        this.view = DUMMY;
-        compositeDisposable.clear();
-    }
-
-    /**
-     * asks the repository to fetch categories for the query
-     *  @param query
-     *
-     */
-    @Override
-    public void searchForCategories(String query) {
-        List<CategoryItem> categoryItems = new ArrayList<>();
-        List<String> imageTitleList = getImageTitleList();
-        Observable<CategoryItem> distinctCategoriesObservable = Observable
-                .fromIterable(repository.getSelectedCategories())
-                .subscribeOn(ioScheduler)
-                .observeOn(mainThreadScheduler)
-                .doOnSubscribe(disposable -> {
-                    view.showProgress(true);
-                    view.showError(null);
-                    view.setCategories(null);
-                })
-                .observeOn(ioScheduler)
-                .concatWith(
-                        repository.searchAll(query, imageTitleList)
-                )
-                .filter(categoryItem -> !repository.containsYear(categoryItem.getName()))
-                .distinct();
-
-        if(!TextUtils.isEmpty(query)) {
-            distinctCategoriesObservable=distinctCategoriesObservable.sorted(repository.sortBySimilarity(query));
-        }
-        Disposable searchCategoriesDisposable = distinctCategoriesObservable
-                .observeOn(mainThreadScheduler)
-                .subscribe(
-                        s -> categoryItems.add(s),
-                        Timber::e,
-                        () -> {
-                            view.setCategories(categoryItems);
-                            view.showProgress(false);
-
-                            if (categoryItems.isEmpty()) {
-                                view.showError(R.string.no_categories_found);
-                            }
-                        }
-                );
-
-        compositeDisposable.add(searchCategoriesDisposable);
-    }
-
-    /**
-     * Returns image title list from UploadItem
-     * @return
-     */
-    private List<String> getImageTitleList() {
-        List<String> titleList = new ArrayList<>();
-        for (UploadItem item : repository.getUploads()) {
-            final String captionText = item.getUploadMediaDetails().get(0).getCaptionText();
-            if (!TextUtils.isEmpty(captionText)) {
-                titleList.add(captionText);
-            }
-        }
-        return titleList;
-    }
-
-    /**
-     * Verifies the number of categories selected, prompts the user if none selected
-     */
-    @Override
-    public void verifyCategories() {
-        List<CategoryItem> selectedCategories = repository.getSelectedCategories();
-        if (selectedCategories != null && !selectedCategories.isEmpty()) {
-            repository.setSelectedCategories(repository.getCategoryStringList());
-            view.goToNextScreen();
-        } else {
-            view.showNoCategorySelected();
-        }
-    }
-
-    /**
-     * ask repository to handle category clicked
-     *
-     * @param categoryItem
-     */
-    @Override
-    public void onCategoryItemClicked(CategoryItem categoryItem) {
-        repository.onCategoryClicked(categoryItem);
-    }
-}

app/src/main/java/fr/free/nrw/commons/upload/categories/CategoriesPresenter.kt

@@ -0,0 +1,111 @@
+package fr.free.nrw.commons.upload.categories
+
+import android.text.TextUtils
+import fr.free.nrw.commons.R
+import fr.free.nrw.commons.category.CategoryItem
+import fr.free.nrw.commons.di.CommonsApplicationModule
+import fr.free.nrw.commons.repository.UploadRepository
+import fr.free.nrw.commons.upload.depicts.proxy
+import io.reactivex.Scheduler
+import io.reactivex.disposables.CompositeDisposable
+import io.reactivex.subjects.PublishSubject
+import timber.log.Timber
+import javax.inject.Inject
+import javax.inject.Named
+import javax.inject.Singleton
+
+/**
+ * The presenter class for UploadCategoriesFragment
+ */
+@Singleton
+class CategoriesPresenter @Inject constructor(
+    private val repository: UploadRepository,
+    @param:Named(CommonsApplicationModule.IO_THREAD) private val ioScheduler: Scheduler,
+    @param:Named(CommonsApplicationModule.MAIN_THREAD) private val mainThreadScheduler: Scheduler
+) : CategoriesContract.UserActionListener {
+
+    companion object {
+        private val DUMMY: CategoriesContract.View = proxy()
+    }
+
+    var view = DUMMY
+    private val compositeDisposable = CompositeDisposable()
+    private val searchTerms = PublishSubject.create<String>()
+
+    override fun onAttachView(view: CategoriesContract.View) {
+        this.view = view
+        compositeDisposable.add(
+            searchTerms
+                .observeOn(mainThreadScheduler)
+                .doOnNext {
+                    view.showProgress(true)
+                    view.showError(null)
+                    view.setCategories(null)
+                }
+                .switchMap(::searchResults)
+                .map { repository.selectedCategories + it }
+                .map { it.distinctBy { categoryItem -> categoryItem.name } }
+                .observeOn(mainThreadScheduler)
+                .subscribe(
+                    {
+                        view.setCategories(it)
+                        view.showProgress(false)
+                        if (it.isEmpty()) {
+                            view.showError(R.string.no_categories_found)
+                        }
+                    },
+                    Timber::e
+                )
+        )
+    }
+
+    private fun searchResults(term: String) =
+        repository.searchAll(term, getImageTitleList())
+            .subscribeOn(ioScheduler)
+            .map { it.filterNot { categoryItem -> repository.containsYear(categoryItem.name) } }
+
+    override fun onDetachView() {
+        view = DUMMY
+        compositeDisposable.clear()
+    }
+
+    /**
+     * asks the repository to fetch categories for the query
+     * @param query
+     */
+    override fun searchForCategories(query: String) {
+        searchTerms.onNext(query)
+    }
+
+    /**
+     * Returns image title list from UploadItem
+     * @return
+     */
+    private fun getImageTitleList(): List<String> {
+        return repository.uploads
+            .map { it.uploadMediaDetails[0].captionText }
+            .filterNot { TextUtils.isEmpty(it) }
+    }
+
+    /**
+     * Verifies the number of categories selected, prompts the user if none selected
+     */
+    override fun verifyCategories() {
+        val selectedCategories = repository.selectedCategories
+        if (selectedCategories.isNotEmpty()) {
+            repository.setSelectedCategories(selectedCategories.map { it.name })
+            view.goToNextScreen()
+        } else {
+            view.showNoCategorySelected()
+        }
+    }
+
+    /**
+     * ask repository to handle category clicked
+     *
+     * @param categoryItem
+     */
+    override fun onCategoryItemClicked(categoryItem: CategoryItem) {
+        repository.onCategoryClicked(categoryItem)
+    }
+}

app/src/main/java/fr/free/nrw/commons/upload/categories/UploadCategoriesFragment.java

@@ -1,6 +1,7 @@
 package fr.free.nrw.commons.upload.categories;
 
 import android.os.Bundle;
+import android.text.Editable;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
@@ -50,8 +51,6 @@ public class UploadCategoriesFragment extends UploadBaseFragment implements Cate
     CategoriesContract.UserActionListener presenter;
     private RVRendererAdapter<CategoryItem> adapter;
     private Disposable subscribe;
-    private List<CategoryItem> categories;
-    private boolean isVisible;
 
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
@@ -78,15 +77,6 @@ public class UploadCategoriesFragment extends UploadBaseFragment implements Cate
         presenter.onAttachView(this);
         initRecyclerView();
         addTextChangeListenerToEtSearch();
-        //get default categories for empty query
-    }
-
-    @Override
-    public void onResume() {
-        super.onResume();
-        if (presenter != null && isVisible && (categories == null || categories.isEmpty())) {
-            presenter.searchForCategories(null);
-        }
     }
 
     private void addTextChangeListenerToEtSearch() {
@@ -135,7 +125,6 @@ public class UploadCategoriesFragment extends UploadBaseFragment implements Cate
     public void setCategories(List<CategoryItem> categories) {
         adapter.clear();
         if (categories != null) {
-            this.categories = categories;
             adapter.addAll(categories);
             adapter.notifyDataSetChanged();
         }
@@ -174,12 +163,11 @@ public class UploadCategoriesFragment extends UploadBaseFragment implements Cate
     }
 
     @Override
-    public void setUserVisibleHint(boolean isVisibleToUser) {
+    protected void onBecameVisible() {
-        super.setUserVisibleHint(isVisibleToUser);
+        super.onBecameVisible();
-        isVisible = isVisibleToUser;
+        final Editable text = etSearch.getText();
-
+        if (text != null) {
-        if (presenter != null && isResumed() && (categories == null || categories.isEmpty())) {
+            presenter.searchForCategories(text.toString());
-            presenter.searchForCategories(null);
         }
     }
 }

app/src/test/kotlin/fr/free/nrw/commons/category/CategoriesModelTest.kt

@@ -2,14 +2,11 @@ package fr.free.nrw.commons.category
 
 import com.nhaarman.mockitokotlin2.mock
 import com.nhaarman.mockitokotlin2.whenever
-import fr.free.nrw.commons.kvstore.JsonKvStore
 import fr.free.nrw.commons.upload.GpsCategoryModel
 import io.reactivex.Observable
-import junit.framework.Assert.assertEquals
+import io.reactivex.subjects.BehaviorSubject
 import org.junit.Before
 import org.junit.Test
-import org.mockito.ArgumentMatchers.anyString
-import org.mockito.ArgumentMatchers.eq
 import org.mockito.Mock
 import org.mockito.MockitoAnnotations
 
@@ -31,48 +28,41 @@ class CategoriesModelTest {
     // Test Case for verifying that Categories search (MW api calls) are case-insensitive
     @Test
     fun searchAllFoundCaseTest() {
-        val categoriesModel = CategoriesModel(categoryClient, null, null, mock())
+        val categoriesModel = CategoriesModel(categoryClient, mock(), mock())
 
-        whenever(categoryClient.searchCategoriesForPrefix(anyString(), eq(25)))
+        val expectedList = listOf("Test")
-            .thenReturn(Observable.just("Test"))
+        whenever(categoryClient.searchCategoriesForPrefix("tes", 25))
+            .thenReturn(Observable.just(expectedList))
 
         // Checking if both return "Test"
-        val actualCategoryName = categoriesModel.searchAll("tes", null).blockingFirst()
+        val expectedItems = expectedList.map { CategoryItem(it, false) }
-        assertEquals("Test", actualCategoryName.name)
+        categoriesModel.searchAll("tes", emptyList())
+            .test()
+            .assertValues(expectedItems)
 
-        val actualCategoryNameCaps = categoriesModel.searchAll("Tes", null).blockingFirst()
+        categoriesModel.searchAll("Tes", emptyList())
-        assertEquals("Test", actualCategoryNameCaps.name)
+            .test()
+            .assertValues(expectedItems)
     }
 
-    /**
-     * For testing the substring search algorithm for Categories search
-     * To be more precise it tests the In Between substring( ex: searching `atte`
-     * will give search suggestions: `Latte`, `Iced latte` e.t.c) which has been described
-     * on github repo wiki:
-     * https://github.com/commons-app/apps-android-commons/wiki/Category-suggestions-(readme)#user-content-3-category-search-when-typing-in-the-search-field-has-been-made-more-flexible
-     */
     @Test
-    fun searchAllFoundCaseTestForSubstringSearch() {
+    fun `searchAll with empty search terms creates results from gps, title search & recents`() {
         val gpsCategoryModel: GpsCategoryModel = mock()
-        val kvStore: JsonKvStore = mock()
 
-        whenever(gpsCategoryModel.categoryList).thenReturn(listOf("gpsCategory"))
+        whenever(gpsCategoryModel.categoriesFromLocation)
+            .thenReturn(BehaviorSubject.createDefault(listOf("gpsCategory")))
         whenever(categoryClient.searchCategories("tes", 25))
-            .thenReturn(Observable.just("tes"))
+            .thenReturn(Observable.just(listOf("titleSearch")))
-        whenever(kvStore.getString("Category", "")).thenReturn("Random Value")
         whenever(categoryDao.recentCategories(25)).thenReturn(listOf("recentCategories"))
-        CategoriesModel(
+        CategoriesModel(categoryClient, categoryDao, gpsCategoryModel)
-            categoryClient,
+            .searchAll("", listOf("tes"))
-            categoryDao,
-            kvStore,
-            gpsCategoryModel
-        ).searchAll(null, listOf("tes"))
             .test()
-            .assertValues(
+            .assertValue(
-                CategoryItem("gpsCategory", false),
+                listOf(
-                CategoryItem("tes", false),
+                    CategoryItem("gpsCategory", false),
-                CategoryItem("Random Value", false),
+                    CategoryItem("titleSearch", false),
-                CategoryItem("recentCategories", false)
+                    CategoryItem("recentCategories", false)
+                )
             )
     }
 }

app/src/test/kotlin/fr/free/nrw/commons/category/CategoryClientTest.kt

@@ -1,20 +1,26 @@
 package fr.free.nrw.commons.category
 
+import com.nhaarman.mockitokotlin2.mock
+import com.nhaarman.mockitokotlin2.whenever
 import io.reactivex.Observable
-import junit.framework.Assert.*
 import org.junit.Before
 import org.junit.Test
-import org.mockito.*
+import org.mockito.ArgumentMatchers.anyInt
+import org.mockito.ArgumentMatchers.anyString
+import org.mockito.InjectMocks
+import org.mockito.Mock
+import org.mockito.Mockito.mock
+import org.mockito.MockitoAnnotations
 import org.wikipedia.dataclient.mwapi.MwQueryPage
 import org.wikipedia.dataclient.mwapi.MwQueryResponse
 import org.wikipedia.dataclient.mwapi.MwQueryResult
 
 class CategoryClientTest {
     @Mock
-    internal var categoryInterface: CategoryInterface? = null
+    internal lateinit var categoryInterface: CategoryInterface
 
     @InjectMocks
-    var categoryClient: CategoryClient? = null
+    lateinit var categoryClient: CategoryClient
 
     @Before
     @Throws(Exception::class)
@@ -24,132 +30,111 @@ class CategoryClientTest {
 
     @Test
     fun searchCategoriesFound() {
-        val mwQueryPage = Mockito.mock(MwQueryPage::class.java)
+        val mockResponse = withMockResponse("Category:Test")
-        Mockito.`when`(mwQueryPage.title()).thenReturn("Category:Test")
+        whenever(categoryInterface.searchCategories(anyString(), anyInt(), anyInt()))
-        val mwQueryResult = Mockito.mock(MwQueryResult::class.java)
+            .thenReturn(Observable.just(mockResponse))
-        Mockito.`when`(mwQueryResult.pages()).thenReturn(listOf(mwQueryPage))
+        categoryClient.searchCategories("tes", 10)
-        val mockResponse = Mockito.mock(MwQueryResponse::class.java)
+            .test()
-        Mockito.`when`(mockResponse.query()).thenReturn(mwQueryResult)
+            .assertValues(listOf("Test"))
-
+        categoryClient.searchCategories("tes", 10, 10)
-        Mockito.`when`(categoryInterface!!.searchCategories(ArgumentMatchers.anyString(), ArgumentMatchers.anyInt(), ArgumentMatchers.anyInt()))
+            .test()
-                .thenReturn(Observable.just(mockResponse))
+            .assertValues(listOf("Test"))
-
-        val actualCategoryName = categoryClient!!.searchCategories("tes", 10).blockingFirst()
-        assertEquals("Test", actualCategoryName)
-
-        val actualCategoryName2 = categoryClient!!.searchCategories("tes", 10, 10).blockingFirst()
-        assertEquals("Test", actualCategoryName2)
     }
 
     @Test
     fun searchCategoriesNull() {
-        val mwQueryResult = Mockito.mock(MwQueryResult::class.java)
+        val mockResponse = withNullPages()
-        Mockito.`when`(mwQueryResult.pages()).thenReturn(null)
+        whenever(categoryInterface.searchCategories(anyString(), anyInt(), anyInt()))
-        val mockResponse = Mockito.mock(MwQueryResponse::class.java)
+            .thenReturn(Observable.just(mockResponse))
-        Mockito.`when`(mockResponse.query()).thenReturn(mwQueryResult)
+        categoryClient.searchCategories("tes", 10)
-
+            .test()
-        Mockito.`when`(categoryInterface!!.searchCategories(ArgumentMatchers.anyString(), ArgumentMatchers.anyInt(), ArgumentMatchers.anyInt()))
+            .assertValues(emptyList())
-                .thenReturn(Observable.just(mockResponse))
+        categoryClient.searchCategories("tes", 10, 10)
-
+            .test()
-        categoryClient!!.searchCategories("tes", 10).subscribe(
+            .assertValues(emptyList())
-                { fail("SearchCategories returned element when it shouldn't have.") },
-                { s -> throw s })
-        categoryClient!!.searchCategories("tes", 10, 10).subscribe(
-                { fail("SearchCategories returned element when it shouldn't have.") },
-                { s -> throw s })
     }
 
     @Test
     fun searchCategoriesForPrefixFound() {
-        val mwQueryPage = Mockito.mock(MwQueryPage::class.java)
+        val mockResponse = withMockResponse("Category:Test")
-        Mockito.`when`(mwQueryPage.title()).thenReturn("Category:Test")
+        whenever(categoryInterface.searchCategoriesForPrefix(anyString(), anyInt(), anyInt()))
-        val mwQueryResult = Mockito.mock(MwQueryResult::class.java)
+            .thenReturn(Observable.just(mockResponse))
-        Mockito.`when`(mwQueryResult.pages()).thenReturn(listOf(mwQueryPage))
+        categoryClient.searchCategoriesForPrefix("tes", 10)
-        val mockResponse = Mockito.mock(MwQueryResponse::class.java)
+            .test()
-        Mockito.`when`(mockResponse.query()).thenReturn(mwQueryResult)
+            .assertValues(listOf("Test"))
-
+        categoryClient.searchCategoriesForPrefix("tes", 10, 10)
-        Mockito.`when`(categoryInterface!!.searchCategoriesForPrefix(ArgumentMatchers.anyString(), ArgumentMatchers.anyInt(), ArgumentMatchers.anyInt()))
+            .test()
-                .thenReturn(Observable.just(mockResponse))
+            .assertValues(listOf("Test"))
-
-        val actualCategoryName = categoryClient!!.searchCategoriesForPrefix("tes", 10).blockingFirst()
-        assertEquals("Test", actualCategoryName)
-        val actualCategoryName2 = categoryClient!!.searchCategoriesForPrefix("tes", 10, 10).blockingFirst()
-        assertEquals("Test", actualCategoryName2)
     }
 
     @Test
     fun searchCategoriesForPrefixNull() {
-        val mwQueryResult = Mockito.mock(MwQueryResult::class.java)
+        val mockResponse = withNullPages()
-        Mockito.`when`(mwQueryResult.pages()).thenReturn(null)
+        whenever(categoryInterface.searchCategoriesForPrefix(anyString(), anyInt(), anyInt()))
-        val mockResponse = Mockito.mock(MwQueryResponse::class.java)
+            .thenReturn(Observable.just(mockResponse))
-        Mockito.`when`(mockResponse.query()).thenReturn(mwQueryResult)
+        categoryClient.searchCategoriesForPrefix("tes", 10)
-
+            .test()
-        Mockito.`when`(categoryInterface!!.searchCategoriesForPrefix(ArgumentMatchers.anyString(), ArgumentMatchers.anyInt(), ArgumentMatchers.anyInt()))
+            .assertValues(emptyList())
-                .thenReturn(Observable.just(mockResponse))
+        categoryClient.searchCategoriesForPrefix("tes", 10, 10)
-        categoryClient!!.searchCategoriesForPrefix("tes", 10).subscribe(
+            .test()
-                { fail("SearchCategories returned element when it shouldn't have.") },
+            .assertValues(emptyList())
-                { s -> throw s })
-        categoryClient!!.searchCategoriesForPrefix("tes", 10, 10).subscribe(
-                { fail("SearchCategories returned element when it shouldn't have.") },
-                { s -> throw s })
     }
 
     @Test
     fun getParentCategoryListFound() {
-        val mwQueryPage = Mockito.mock(MwQueryPage::class.java)
+        val mockResponse = withMockResponse("Category:Test")
-        Mockito.`when`(mwQueryPage.title()).thenReturn("Category:Test")
+        whenever(categoryInterface.getParentCategoryList(anyString()))
-        val mwQueryResult = Mockito.mock(MwQueryResult::class.java)
+            .thenReturn(Observable.just(mockResponse))
-        Mockito.`when`(mwQueryResult.pages()).thenReturn(listOf(mwQueryPage))
+        categoryClient.getParentCategoryList("tes")
-        val mockResponse = Mockito.mock(MwQueryResponse::class.java)
+            .test()
-        Mockito.`when`(mockResponse.query()).thenReturn(mwQueryResult)
+            .assertValues(listOf("Test"))
-
-        Mockito.`when`(categoryInterface!!.getParentCategoryList(ArgumentMatchers.anyString()))
-                .thenReturn(Observable.just(mockResponse))
-
-        val actualCategoryName = categoryClient!!.getParentCategoryList("tes").blockingFirst()
-        assertEquals("Test", actualCategoryName)
     }
 
     @Test
     fun getParentCategoryListNull() {
-        val mwQueryResult = Mockito.mock(MwQueryResult::class.java)
+        val mockResponse = withNullPages()
-        Mockito.`when`(mwQueryResult.pages()).thenReturn(null)
+        whenever(categoryInterface.getParentCategoryList(anyString()))
-        val mockResponse = Mockito.mock(MwQueryResponse::class.java)
+            .thenReturn(Observable.just(mockResponse))
-        Mockito.`when`(mockResponse.query()).thenReturn(mwQueryResult)
+        categoryClient.getParentCategoryList("tes")
-
+            .test()
-        Mockito.`when`(categoryInterface!!.getParentCategoryList(ArgumentMatchers.anyString()))
+            .assertValues(emptyList())
-                .thenReturn(Observable.just(mockResponse))
-        categoryClient!!.getParentCategoryList("tes").subscribe(
-                { fail("SearchCategories returned element when it shouldn't have.") },
-                { s -> throw s })
     }
+
     @Test
     fun getSubCategoryListFound() {
-        val mwQueryPage = Mockito.mock(MwQueryPage::class.java)
+        val mockResponse = withMockResponse("Category:Test")
-        Mockito.`when`(mwQueryPage.title()).thenReturn("Category:Test")
+        whenever(categoryInterface.getSubCategoryList("tes"))
-        val mwQueryResult = Mockito.mock(MwQueryResult::class.java)
+            .thenReturn(Observable.just(mockResponse))
-        Mockito.`when`(mwQueryResult.pages()).thenReturn(listOf(mwQueryPage))
+        categoryClient.getSubCategoryList("tes")
-        val mockResponse = Mockito.mock(MwQueryResponse::class.java)
+            .test()
-        Mockito.`when`(mockResponse.query()).thenReturn(mwQueryResult)
+            .assertValues(listOf("Test"))
-
-        Mockito.`when`(categoryInterface!!.getSubCategoryList(ArgumentMatchers.anyString()))
-                .thenReturn(Observable.just(mockResponse))
-
-        val actualCategoryName = categoryClient!!.getSubCategoryList("tes").blockingFirst()
-        assertEquals("Test", actualCategoryName)
     }
 
     @Test
     fun getSubCategoryListNull() {
-        val mwQueryResult = Mockito.mock(MwQueryResult::class.java)
+        val mockResponse = withNullPages()
-        Mockito.`when`(mwQueryResult.pages()).thenReturn(null)
+        whenever(categoryInterface.getSubCategoryList(anyString()))
-        val mockResponse = Mockito.mock(MwQueryResponse::class.java)
+            .thenReturn(Observable.just(mockResponse))
-        Mockito.`when`(mockResponse.query()).thenReturn(mwQueryResult)
+        categoryClient.getSubCategoryList("tes")
+            .test()
+            .assertValues(emptyList())
+    }
 
-        Mockito.`when`(categoryInterface!!.getSubCategoryList(ArgumentMatchers.anyString()))
+    private fun withMockResponse(title: String): MwQueryResponse? {
-                .thenReturn(Observable.just(mockResponse))
+        val mwQueryPage: MwQueryPage = mock()
-        categoryClient!!.getSubCategoryList("tes").subscribe(
+        whenever(mwQueryPage.title()).thenReturn(title)
-                { fail("SearchCategories returned element when it shouldn't have.") },
+        val mwQueryResult: MwQueryResult = mock()
-                { s -> throw s })
+        whenever(mwQueryResult.pages()).thenReturn(listOf(mwQueryPage))
+        val mockResponse = mock(MwQueryResponse::class.java)
+        whenever(mockResponse.query()).thenReturn(mwQueryResult)
+        return mockResponse
+    }
+
+    private fun withNullPages(): MwQueryResponse? {
+        val mwQueryResult = mock(MwQueryResult::class.java)
+        whenever(mwQueryResult.pages()).thenReturn(null)
+        val mockResponse = mock(MwQueryResponse::class.java)
+        whenever(mockResponse.query()).thenReturn(mwQueryResult)
+        return mockResponse
     }
 }

app/src/test/kotlin/fr/free/nrw/commons/upload/CategoriesPresenterTest.kt

@@ -1,7 +1,7 @@
 package fr.free.nrw.commons.upload
 
-import com.nhaarman.mockitokotlin2.verify
+import com.nhaarman.mockitokotlin2.*
-import com.nhaarman.mockitokotlin2.whenever
+import fr.free.nrw.commons.R
 import fr.free.nrw.commons.category.CategoryItem
 import fr.free.nrw.commons.repository.UploadRepository
 import fr.free.nrw.commons.upload.categories.CategoriesContract
@@ -10,7 +10,6 @@ import io.reactivex.Observable
 import io.reactivex.schedulers.TestScheduler
 import org.junit.Before
 import org.junit.Test
-import org.mockito.ArgumentMatchers
 import org.mockito.Mock
 import org.mockito.MockitoAnnotations
 
@@ -20,6 +19,7 @@ import org.mockito.MockitoAnnotations
 class CategoriesPresenterTest {
     @Mock
     internal lateinit var repository: UploadRepository
+
     @Mock
     internal lateinit var view: CategoriesContract.View
 
@@ -49,30 +49,76 @@ class CategoriesPresenterTest {
      * unit test case for method CategoriesPresenter.searchForCategories
      */
     @Test
-    fun searchForCategoriesTest() {
+    fun `searchForCategories combines selection and search results without years distinctly`() {
-        whenever(repository.sortBySimilarity(ArgumentMatchers.anyString())).thenReturn(Comparator<CategoryItem> { _, _ -> 1 })
+        val nonEmptyCaptionUploadItem = mock<UploadItem>()
-        whenever(repository.selectedCategories).thenReturn(categoryItems)
+        whenever(nonEmptyCaptionUploadItem.uploadMediaDetails)
-        whenever(repository.searchAll(ArgumentMatchers.anyString(), ArgumentMatchers.anyList())).thenReturn(Observable.empty())
+            .thenReturn(listOf(UploadMediaDetail(captionText = "nonEmpty")))
+        val emptyCaptionUploadItem = mock<UploadItem>()
+        whenever(emptyCaptionUploadItem.uploadMediaDetails)
+            .thenReturn(listOf(UploadMediaDetail(captionText = "")))
+        whenever(repository.uploads).thenReturn(
+            listOf(
+                nonEmptyCaptionUploadItem,
+                emptyCaptionUploadItem
+            )
+        )
+        whenever(repository.searchAll("test", listOf("nonEmpty")))
+            .thenReturn(
+                Observable.just(
+                    listOf(
+                        categoryItem("selected"),
+                        categoryItem("doesContainYear")
+                    )
+                )
+            )
+        whenever(repository.containsYear("selected")).thenReturn(false)
+        whenever(repository.containsYear("doesContainYear")).thenReturn(true)
+        whenever(repository.selectedCategories).thenReturn(listOf(categoryItem("selected", true)))
         categoriesPresenter.searchForCategories("test")
+        testScheduler.triggerActions()
         verify(view).showProgress(true)
         verify(view).showError(null)
         verify(view).setCategories(null)
-        testScheduler.triggerActions()
+        verify(view).setCategories(listOf(categoryItem("selected", true)))
-        verify(view).setCategories(categoryItems)
         verify(view).showProgress(false)
+        verifyNoMoreInteractions(view)
+    }
+
+    @Test
+    fun `searchForCategoriesTest sets Error when list is empty`() {
+        whenever(repository.uploads).thenReturn(listOf())
+        whenever(repository.searchAll(any(), any())).thenReturn(Observable.just(listOf()))
+        whenever(repository.selectedCategories).thenReturn(listOf())
+        categoriesPresenter.searchForCategories("test")
+        testScheduler.triggerActions()
+        verify(view).showProgress(true)
+        verify(view).showError(null)
+        verify(view).setCategories(null)
+        verify(view).setCategories(listOf())
+        verify(view).showProgress(false)
+        verify(view).showError(R.string.no_categories_found)
+        verifyNoMoreInteractions(view)
     }
 
     /**
      * unit test for method CategoriesPresenter.verifyCategories
      */
     @Test
-    fun verifyCategoriesTest() {
+    fun `verifyCategories with non empty selection goes to next screen`() {
-        whenever(repository.selectedCategories).thenReturn(categoryItems)
+        val item = categoryItem()
+        whenever(repository.selectedCategories).thenReturn(listOf(item))
         categoriesPresenter.verifyCategories()
-        verify(repository).setSelectedCategories(ArgumentMatchers.anyList())
+        verify(repository).setSelectedCategories(listOf(item.name))
         verify(view).goToNextScreen()
     }
 
+    @Test
+    fun `verifyCategories with empty selection show no category selected`() {
+        whenever(repository.selectedCategories).thenReturn(listOf())
+        categoriesPresenter.verifyCategories()
+        verify(view).showNoCategorySelected()
+    }
+
     /**
      * Test onCategory Item clicked
      */
@@ -81,4 +127,7 @@ class CategoriesPresenterTest {
         categoriesPresenter.onCategoryItemClicked(categoryItem)
         verify(repository).onCategoryClicked(categoryItem)
     }
+
+    private fun categoryItem(name: String = "name", selected: Boolean = false) =
+        CategoryItem(name, selected)
 }

app/src/test/kotlin/fr/free/nrw/commons/upload/GpsCategoryModelTest.kt

@@ -1,76 +1,33 @@
 package fr.free.nrw.commons.upload
 
-import org.junit.Assert.*
 import org.junit.Before
 import org.junit.Test
 
 class GpsCategoryModelTest {
-
+    lateinit var gpsCategoryModel: GpsCategoryModel
-    private lateinit var testObject: GpsCategoryModel
 
     @Before
     fun setUp() {
-        testObject = GpsCategoryModel()
+        gpsCategoryModel = GpsCategoryModel()
     }
 
     @Test
-    fun initiallyTheModelIsEmpty() {
+    fun `intial value is empty`() {
-        assertFalse(testObject.gpsCatExists)
+        gpsCategoryModel.categoriesFromLocation.test().assertValues(emptyList())
-        assertTrue(testObject.categoryList.isEmpty())
     }
 
     @Test
-    fun addingCategoriesToTheModel() {
+    fun `setCategoriesFromLocation emits the new value`() {
-        testObject.categoryList = listOf("one")
+        val expectedList = listOf("category")
-        assertTrue(testObject.gpsCatExists)
+        gpsCategoryModel.categoriesFromLocation.test()
-        assertFalse(testObject.categoryList.isEmpty())
+            .also { gpsCategoryModel.setCategoriesFromLocation(expectedList) }
-        assertEquals(listOf("one"), testObject.categoryList)
+            .assertValues(emptyList(), expectedList)
     }
 
     @Test
-    fun duplicatesAreIgnored() {
+    fun `clear emits an empty value`() {
-        testObject.categoryList = listOf("one", "one")
+        gpsCategoryModel.categoriesFromLocation.test()
-        assertEquals(listOf("one"), testObject.categoryList)
+            .also { gpsCategoryModel.clear() }
-    }
+            .assertValues(emptyList(), emptyList())
-
-    @Test
-    fun modelProtectsAgainstExternalModification() {
-        testObject.categoryList = listOf("one")
-
-        val list = testObject.categoryList
-        list.add("two")
-
-        assertEquals(listOf("one"), testObject.categoryList)
-    }
-
-    @Test
-    fun clearingTheModel() {
-        testObject.categoryList = listOf("one")
-
-        testObject.clear()
-        assertFalse(testObject.gpsCatExists)
-        assertTrue(testObject.categoryList.isEmpty())
-
-        testObject.categoryList = listOf("two")
-        assertEquals(listOf("two"), testObject.categoryList)
-    }
-
-    @Test
-    fun settingTheListHandlesNull() {
-        testObject.categoryList = listOf("one")
-
-        testObject.categoryList = null
-
-        assertFalse(testObject.gpsCatExists)
-        assertTrue(testObject.categoryList.isEmpty())
-    }
-
-    @Test
-    fun settingTheListOverwritesExistingValues() {
-        testObject.categoryList = listOf("one")
-
-        testObject.categoryList = listOf("two")
-
-        assertEquals(listOf("two"), testObject.categoryList)
     }
 }