Migrated tests to JUnit.

.github/disabled_workflows/font.yml

@@ -1,51 +0,0 @@
-#
-# MIT License
-#
-# Copyright (c) 2020 Jannis Weis
-#
-# Permission is hereby granted, free of charge, to any person obtaining a copy
-# of this software and associated documentation files (the "Software"), to deal
-# in the Software without restriction, including without limitation the rights
-# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-# copies of the Software, and to permit persons to whom the Software is
-# furnished to do so, subject to the following conditions:
-#
-# The above copyright notice and this permission notice shall be included in all
-# copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-# SOFTWARE.
-#
-#
-name: Fonts
-
-on:
-  push:
-    branches:
-      - 'master'
-jobs:
-  gradle:
-    strategy:
-      matrix:
-        os: [windows-latest, macos-latest, ubuntu-latest]
-    runs-on: ${{ matrix.os }}
-    steps:
-      - uses: actions/checkout@v2
-        with:
-          fetch-depth: 10
-      - name: Set up JDK 11
-        uses: actions/setup-java@v1
-        with:
-          java-version: 11
-      - name: Build
-        run: ./gradlew :darklaf-core:fontTest -PskipAutostyle
-      - name: Upload Results
-        uses: actions/upload-artifact@v1
-        with:
-          name: ${{ matrix.os }}-font_test
-          path: build/font_test

.github/workflows/gradle.yml

@@ -45,6 +45,13 @@ jobs:
           java-version: 11
       - name: Build
         run: ./gradlew build -PskipAutostyle --info
+      - name: Test
+        run: ./gradlew :darklaf-core:test -PskipAutostyle
+      - name: Upload Results
+        uses: actions/upload-artifact@v1
+        with:
+          name: windows-test-results
+          path: build/test_results
 
   linux:
     name: Linux (Java 8)
@@ -59,6 +66,13 @@ jobs:
           java-version: 8
       - name: Build
         run: ./gradlew build -PskipAutostyle --info
+      - name: Test
+        run: ./gradlew :darklaf-core:test -PskipAutostyle
+      - name: Upload Results
+        uses: actions/upload-artifact@v1
+        with:
+          name: linux-test-results
+          path: build/test_results
 
   macos:
     name: macOS (Java 11)
@@ -73,3 +87,10 @@ jobs:
           java-version: 11
       - name: Build
         run: ./gradlew build -PskipAutostyle --info
+      - name: Test
+        run: ./gradlew :darklaf-core:test -PskipAutostyle
+      - name: Upload Results
+        uses: actions/upload-artifact@v1
+        with:
+          name: macOS-test-results
+          path: build/test_results

core/build.gradle.kts

@@ -17,6 +17,14 @@ dependencies {
     testImplementation("com.miglayout:miglayout-core")
     testImplementation("com.miglayout:miglayout-swing")
     testImplementation("org.swinglabs:swingx")
+    testImplementation("org.junit.jupiter:junit-jupiter-api")
+    testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine")
+}
+
+tasks.test {
+    useJUnitPlatform()
+    workingDir = File(project.rootDir, "build/test_results")
+    workingDir.mkdirs()
 }
 
 val makeDocumentation by tasks.registering(JavaExec::class) {
@@ -30,17 +38,6 @@ val makeDocumentation by tasks.registering(JavaExec::class) {
     classpath(sourceSets.main.get().runtimeClasspath, sourceSets.test.get().runtimeClasspath)
 }
 
-val fontTest by tasks.registering(JavaExec::class) {
-    group = "Verification"
-    description = "Creates font sample images"
-    dependsOn(tasks.testClasses)
-
-    workingDir = File(project.rootDir, "build")
-    workingDir.mkdirs()
-    main = "FontTest"
-    classpath(sourceSets.main.get().runtimeClasspath, sourceSets.test.get().runtimeClasspath)
-}
-
 abstract class DemoTask : JavaExec() {
     init {
         main = "DemoLauncher"

core/src/main/java/com/github/weisj/darklaf/graphics/ImageUtil.java

@@ -135,9 +135,9 @@ public final class ImageUtil {
         BufferedImage image;
         boolean scale = scalex != 1.0 || scaley != 1.0;
         if (scale) {
-            image = createCompatibleImage((int) (scalex * bounds.width), (int) (scaley * bounds.height));
+            image = createCompatibleTranslucentImage((int) (scalex * bounds.width), (int) (scaley * bounds.height));
         } else {
-            image = createCompatibleImage(bounds.width, bounds.height);
+            image = createCompatibleTranslucentImage(bounds.width, bounds.height);
         }
         final Graphics2D g2d = (Graphics2D) image.getGraphics();
         if (scale) {

core/src/main/java/com/github/weisj/darklaf/ui/tooltip/DarkToolTipUI.java

@@ -125,11 +125,16 @@ public class DarkToolTipUI extends BasicToolTipUI implements PropertyChangeListe
         toolTip.putClientProperty(DarkPopupFactory.KEY_START_HIDDEN, true);
         toolTip.putClientProperty(DarkPopupFactory.KEY_FORCE_HEAVYWEIGHT, true);
         fadeAnimator = new FadeInAnimator();
-        c.setOpaque(false);
         updateTipText(toolTip);
         updateStyle();
     }
 
+    @Override
+    public void update(final Graphics g, final JComponent c) {
+        // Ensures no background is painted.
+        paint(g, c);
+    }
+
     @Override
     protected void installListeners(final JComponent c) {
         super.installListeners(c);
@@ -168,7 +173,7 @@ public class DarkToolTipUI extends BasicToolTipUI implements PropertyChangeListe
             startAnimation();
         } else {
             Window window = DarkUIUtil.getWindow(c);
-            if (window.getOpacity() != 1 && !transparencySupported(window)) {
+            if (window != null && window.getOpacity() != 1 && !transparencySupported(window)) {
                 window.setOpacity(1);
             }
         }
@@ -236,7 +241,6 @@ public class DarkToolTipUI extends BasicToolTipUI implements PropertyChangeListe
 
     @Override
     public void hierarchyChanged(final HierarchyEvent e) {
-        Window w = SwingUtilities.getWindowAncestor(toolTip);
         if (toolTip.getParent() instanceof JComponent) {
             // For MediumWeightPopup still need to make parent non opaque.
             ((JComponent) toolTip.getParent()).setOpaque(false);

core/src/test/java/ClassFinder.java

@@ -0,0 +1,127 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Jannis Weis
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+import java.io.File;
+import java.io.IOException;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Modifier;
+import java.net.URISyntaxException;
+import java.net.URL;
+import java.util.*;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+public class ClassFinder {
+
+    public static <T> List<T> getInstancesOfType(final Class<T> type, final String... packages) {
+        return getClasses(packages).filter(type::isAssignableFrom)
+                                   .filter(cls -> !cls.isInterface())
+                                   .filter(cls -> !Modifier.isAbstract(cls.getModifiers()))
+                                   .map(ClassFinder::getInstance)
+                                   .filter(Objects::nonNull)
+                                   .map(type::cast)
+                                   .collect(Collectors.toList());
+    }
+
+    private static <T> T getInstance(final Class<T> type) {
+        try {
+            return type.getDeclaredConstructor().newInstance();
+        } catch (InstantiationException
+                 | IllegalAccessException
+                 | InvocationTargetException
+                 | NoSuchMethodException e) {
+            return null;
+        }
+    }
+
+    private static Stream<Class<?>> getClasses(final String... packageNames) {
+        return Stream.of(packageNames).flatMap(wrap(ClassFinder::getClasses));
+    }
+
+    private static Stream<Class<?>> getClasses(final String packageName) throws IOException {
+        ClassLoader classLoader = ClassFinder.class.getClassLoader();
+        String pack = packageName.replace(".", "/");
+        Enumeration<URL> resources = classLoader.getResources(pack);
+        return enumerationAsStream(resources).map(ClassFinder::URLtoFile)
+                                             .filter(Objects::nonNull)
+                                             .map(dir -> findClasses(dir, packageName))
+                                             .flatMap(List::stream);
+    }
+
+    private static File URLtoFile(final URL url) {
+        try {
+            return new File(url.toURI());
+        } catch (URISyntaxException e) {
+            return null;
+        }
+    }
+
+    private static List<Class<?>> findClasses(final File dir, final String packageName) {
+        File directory = dir.getAbsoluteFile();
+        List<Class<?>> classes = new ArrayList<>();
+        File[] files = directory.listFiles();
+        if (files == null) return classes;
+        for (File file : files) {
+            if (file.isDirectory()) {
+                assert !file.getName().contains(".");
+                classes.addAll(findClasses(file, packageName + "." + file.getName()));
+            } else if (file.getName().endsWith(".class")) {
+                try {
+                    classes.add(Class.forName(packageName + '.'
+                                              + file.getName().substring(0, file.getName().length() - 6)));
+                } catch (ClassNotFoundException ignored) {}
+            }
+        }
+        return classes;
+    }
+
+    public static <T> Stream<T> enumerationAsStream(final Enumeration<T> e) {
+        return StreamSupport.stream(Spliterators.spliteratorUnknownSize(new Iterator<T>() {
+            public T next() {
+                return e.nextElement();
+            }
+
+            public boolean hasNext() {
+                return e.hasMoreElements();
+            }
+        }, Spliterator.ORDERED), false);
+    }
+
+    public static <T, K, E extends Throwable> Function<T, K> wrap(final CheckedFunction<T, K, E> wrappee) {
+        return t -> {
+            try {
+                return wrappee.apply(t);
+            } catch (final Throwable e) {
+                throw new RuntimeException(e);
+            }
+        };
+    }
+
+    public interface CheckedFunction<T, K, E extends Throwable> {
+
+        K apply(final T value) throws E;
+    }
+}

core/src/test/java/DemoLauncher.java

@@ -22,46 +22,14 @@
  * SOFTWARE.
  *
  */
-import java.io.File;
-import java.io.IOException;
-import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Modifier;
-import java.net.URISyntaxException;
-import java.net.URL;
 import java.util.*;
-import java.util.function.Function;
 import java.util.stream.Collectors;
-import java.util.stream.Stream;
-import java.util.stream.StreamSupport;
 
 import javax.swing.*;
 
 import ui.ComponentDemo;
 import ui.DemoPanel;
 
-/*
- * MIT License
- *
- * Copyright (c) 2020 Jannis Weis
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- */
 public class DemoLauncher implements ComponentDemo {
 
     public static void main(final String[] args) {
@@ -72,81 +40,12 @@ public class DemoLauncher implements ComponentDemo {
 
     public DemoLauncher() {
         Class<ComponentDemo> demoType = ComponentDemo.class;
-        demoClasses = getClasses("ui", "icon", "defaults").filter(demoType::isAssignableFrom)
+        demoClasses = ClassFinder.getInstancesOfType(demoType, "ui", "icon", "defaults")
-                                                          .filter(cls -> !cls.equals(DemoEntry.class))
+                                 .stream()
-                                                          .filter(cls -> !cls.isInterface())
+                                 .filter(obj -> !(obj instanceof DemoLauncher))
-                                                          .filter(cls -> !Modifier.isAbstract(cls.getModifiers()))
+                                 .map(DemoEntry::new)
-                                                          .map(this::getInstance)
+                                 .sorted(Comparator.comparing(DemoEntry::toString))
-                                                          .filter(Objects::nonNull)
+                                 .collect(Collectors.toList());
-                                                          .map(demoType::cast)
-                                                          .map(DemoEntry::new)
-                                                          .sorted(Comparator.comparing(DemoEntry::toString))
-                                                          .collect(Collectors.toList());
-
-    }
-
-    private <T> T getInstance(final Class<T> type) {
-        try {
-            return type.getDeclaredConstructor().newInstance();
-        } catch (InstantiationException
-                 | IllegalAccessException
-                 | InvocationTargetException
-                 | NoSuchMethodException e) {
-            return null;
-        }
-    }
-
-    private Stream<Class<?>> getClasses(final String... packageNames) {
-        return Stream.of(packageNames).flatMap(wrap(this::getClasses));
-    }
-
-    private Stream<Class<?>> getClasses(final String packageName) throws IOException {
-        ClassLoader classLoader = getClass().getClassLoader();
-        String pack = packageName.replace(".", "/");
-        Enumeration<URL> resources = classLoader.getResources(pack);
-        return enumerationAsStream(resources).map(this::URLtoFile)
-                                             .filter(Objects::nonNull)
-                                             .map(dir -> findClasses(dir, packageName))
-                                             .flatMap(List::stream);
-    }
-
-    private File URLtoFile(final URL url) {
-        try {
-            return new File(url.toURI());
-        } catch (URISyntaxException e) {
-            return null;
-        }
-    }
-
-    private List<Class<?>> findClasses(final File dir, final String packageName) {
-        File directory = dir.getAbsoluteFile();
-        List<Class<?>> classes = new ArrayList<>();
-        File[] files = directory.listFiles();
-        if (files == null) return classes;
-        for (File file : files) {
-            if (file.isDirectory()) {
-                assert !file.getName().contains(".");
-                classes.addAll(findClasses(file, packageName + "." + file.getName()));
-            } else if (file.getName().endsWith(".class")) {
-                try {
-                    classes.add(Class.forName(packageName + '.'
-                                              + file.getName().substring(0, file.getName().length() - 6)));
-                } catch (ClassNotFoundException ignored) {}
-            }
-        }
-        return classes;
-    }
-
-    public <T> Stream<T> enumerationAsStream(final Enumeration<T> e) {
-        return StreamSupport.stream(Spliterators.spliteratorUnknownSize(new Iterator<T>() {
-            public T next() {
-                return e.nextElement();
-            }
-
-            public boolean hasNext() {
-                return e.hasMoreElements();
-            }
-        }, Spliterator.ORDERED), false);
     }
 
     @Override
@@ -167,16 +66,6 @@ public class DemoLauncher implements ComponentDemo {
         return "Demo Launcher";
     }
 
-    private <T, K, E extends Throwable> Function<T, K> wrap(final CheckedFunction<T, K, E> wrappee) {
-        return t -> {
-            try {
-                return wrappee.apply(t);
-            } catch (final Throwable e) {
-                throw new RuntimeException(e);
-            }
-        };
-    }
-
     private static class DemoEntry {
 
         private final ComponentDemo demo;
@@ -194,9 +83,4 @@ public class DemoLauncher implements ComponentDemo {
             return demo.getClass().getSimpleName() + ".java";
         }
     }
-
-    private interface CheckedFunction<T, K, E extends Throwable> {
-
-        K apply(final T value) throws E;
-    }
 }

core/src/test/java/test/AbstractImageTest.java

@@ -0,0 +1,74 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Jannis Weis
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+package test;
+
+import java.awt.*;
+import java.awt.image.BufferedImage;
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+
+import javax.imageio.ImageIO;
+import javax.swing.*;
+
+import com.github.weisj.darklaf.graphics.ImageUtil;
+
+public abstract class AbstractImageTest {
+    private static final int SCALING_FACTOR = 3;
+    protected final static String WORKING_DIR = "image_test";
+    private final String workingDir;
+
+    public AbstractImageTest(final String dir) {
+        this.workingDir = dir != null ? WORKING_DIR + "/" + dir : WORKING_DIR;
+    }
+
+    protected String getWorkingDirectory() {
+        return workingDir;
+    }
+
+    protected void createFolder(final String folder) throws IOException {
+        Files.createDirectories(new File(getWorkingDirectory() + "/" + folder).toPath());
+    }
+
+    protected BufferedImage saveScreenShot(final String name, final JComponent c) {
+        return saveScreenShot(name, c, SCALING_FACTOR);
+    }
+
+    protected String getPath(final String name) {
+        return getWorkingDirectory() + "/" + name;
+    }
+
+    protected BufferedImage saveScreenShot(final String name, final JComponent c, final double scalingFactor) {
+        try {
+            Rectangle rect = new Rectangle(0, 0, c.getWidth(), c.getHeight());
+            BufferedImage image = ImageUtil.scaledImageFromComponent(c, rect, scalingFactor, scalingFactor, false);
+            ImageIO.write(image, "png", new File(name + ".png"));
+            return image;
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return null;
+    }
+}

core/src/test/java/test/FontTest.java

@@ -22,39 +22,45 @@
  * SOFTWARE.
  *
  */
+package test;
+
 import java.awt.*;
 import java.awt.font.TextAttribute;
-import java.awt.image.BufferedImage;
-import java.io.File;
 import java.io.IOException;
-import java.nio.file.Files;
 import java.text.AttributedCharacterIterator;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 
-import javax.imageio.ImageIO;
 import javax.swing.*;
 
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.EnabledOnOs;
+import org.junit.jupiter.api.condition.OS;
+
 import ui.DemoResources;
 
 import com.github.weisj.darklaf.LafManager;
-import com.github.weisj.darklaf.graphics.ImageUtil;
 import com.github.weisj.darklaf.theme.IntelliJTheme;
 import com.github.weisj.darklaf.util.SystemInfo;
 
-public class FontTest {
+public class FontTest extends AbstractImageTest {
 
     private static final Map<AttributedCharacterIterator.Attribute, Integer> kerning;
-    private static final int SCALING_FACTOR = 3;
-    private static final String WORKING_DIR = "font_test";
 
     static {
         kerning = Collections.singletonMap(TextAttribute.KERNING, TextAttribute.KERNING_ON);
     }
 
-    public static void main(final String[] args) throws IOException {
+    public FontTest() {
+        super("font");
+    }
+
+    @Test
+    @EnabledOnOs({OS.MAC, OS.WINDOWS, OS.LINUX})
+    public void testFontChoices() throws IOException {
         LafManager.install(new IntelliJTheme());
         JTextArea textArea = new JTextArea();
         textArea.setText(DemoResources.KERNING_TEST);
@@ -85,32 +91,18 @@ public class FontTest {
         }
     }
 
-    private static void createImages(final String folder, final JComponent c,
+    private void createImages(final String folder, final JComponent c,
-                                     final List<FontSpec> fontSpecs) throws IOException {
+                              final List<FontSpec> fontSpecs) throws IOException {
         createFolder(folder);
         for (FontSpec spec : fontSpecs) {
             c.setFont(createFont(spec.fontName));
             setFractionalMetrics(spec.useFractionalMetrics);
-            saveScreenShot(getPath(folder, spec), c);
+            Assertions.assertNotNull(saveScreenShot(getImagePath(folder, spec), c));
         }
     }
 
-    private static void createFolder(final String folder) throws IOException {
+    private String getImagePath(final String folder, final FontSpec spec) {
-        Files.createDirectories(new File(WORKING_DIR + "/" + folder).toPath());
+        return getPath(folder + "/" + spec.getImageName());
-    }
-
-    private static String getPath(final String folder, final FontSpec spec) {
-        return WORKING_DIR + "/" + folder + "/" + spec.getImageName();
-    }
-
-    private static void saveScreenShot(final String name, final JComponent c) {
-        try {
-            Rectangle rect = new Rectangle(0, 0, c.getWidth(), c.getHeight());
-            BufferedImage image = ImageUtil.scaledImageFromComponent(c, rect, SCALING_FACTOR, SCALING_FACTOR, false);
-            ImageIO.write(image, "png", new File(name + ".png"));
-        } catch (IOException e) {
-            e.printStackTrace();
-        }
     }
 
     private static void setFractionalMetrics(final boolean enabled) {

core/src/test/java/test/TooltipTest.java

@@ -0,0 +1,60 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020 Jannis Weis
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+package test;
+
+import java.awt.*;
+import java.awt.image.BufferedImage;
+
+import javax.swing.*;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.EnabledOnOs;
+import org.junit.jupiter.api.condition.OS;
+
+import com.github.weisj.darklaf.LafManager;
+import com.github.weisj.darklaf.ui.tooltip.ToolTipConstants;
+
+public class TooltipTest extends AbstractImageTest {
+
+    public TooltipTest() {
+        super("tooltip");
+    }
+
+    @Test
+    @EnabledOnOs({OS.MAC, OS.WINDOWS})
+    public void testTooltipTransparency() {
+        LafManager.install();
+        JToolTip toolTip = new JToolTip();
+        toolTip.setTipText("Test ToolTip");
+        toolTip.putClientProperty(ToolTipConstants.KEY_STYLE, ToolTipConstants.VARIANT_BALLOON);
+        toolTip.setSize(toolTip.getPreferredSize());
+        toolTip.doLayout();
+        BufferedImage img = saveScreenShot(getPath("tooltip_mac"), toolTip);
+        Assertions.assertNotNull(img);
+        int alpha = new Color(img.getRGB(img.getMinX(), img.getMinY() + img.getHeight() - 1), true).getAlpha();
+        Assertions.assertEquals(0, alpha);
+    }
+}

dependencies-bom/build.gradle.kts

@@ -35,5 +35,7 @@ dependencies {
         apiv("com.formdev:svgSalamander")
         apiv("com.miglayout:miglayout-core", "miglayout")
         apiv("com.miglayout:miglayout-swing", "miglayout")
+        apiv("org.junit.jupiter:junit-jupiter-api", "junit")
+        apiv("org.junit.jupiter:junit-jupiter-engine", "junit")
     }
 }

gradle.properties

@@ -19,3 +19,4 @@ jxlayer.version                                           = 3.0.4
 miglayout.version                                         = 5.2
 swingx.version                                            = 1.6.1
 svgSalamander.version                                     = 1.1.2.1
+junit.version                                             = 5.6.2