added some new unit tests

build.gradle

@@ -60,6 +60,7 @@ allprojects {
             testImplementation 'org.assertj:assertj-core:3.23.1'
             testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.2'
             testImplementation 'org.junit.jupiter:junit-jupiter-params:5.8.2'
+            testImplementation 'org.mockito:mockito-core:4.6.1'
             testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine'
         }
     }

plantuml-plugin/build.gradle

@@ -8,6 +8,7 @@ dependencies {
     //noinspection GradlePackageUpdate
     compileOnly 'net.sourceforge.plantuml:plantuml:1.2022.5'
 
+    testImplementation 'net.sourceforge.plantuml:plantuml:1.2022.5'
 }
 
 gradlePlugin {

plantuml-plugin/src/test/java/io/freefair/gradle/plugins/plantuml/PlantumlPluginTest.java

@@ -1,11 +1,16 @@
 package io.freefair.gradle.plugins.plantuml;
 
 import org.gradle.api.Project;
+import org.gradle.api.file.DirectoryProperty;
+import org.gradle.api.file.RegularFileProperty;
+import org.gradle.api.provider.Property;
 import org.gradle.testfixtures.ProjectBuilder;
 import org.junit.jupiter.api.Test;
 
+import java.io.File;
+
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 class PlantumlPluginTest {
 
@@ -17,4 +22,59 @@ void apply() {
 
         assertThat(project.getTasks().getNames()).contains("plantUml");
     }
+
+    @Test
+    void execute() {
+        Project project = ProjectBuilder.builder().build();
+
+        project.getPlugins().apply(PlantumlPlugin.class);
+
+        PlantumlTask task = project.getTasks().withType(PlantumlTask.class).getByName("plantUml");
+
+        task.source(getClass().getClassLoader().getResource("puml-files").getPath());
+
+        assertThrows(UnsupportedOperationException.class, task::execute);
+    }
+
+    @Test
+    void taskExecution() {
+        Project project = ProjectBuilder.builder().build();
+
+        PlantumlAction action = new PlantumlAction() {
+            @Override
+            public PlantumlParameters getParameters() {
+                return new PlantumlParameters() {
+                    @Override
+                    public RegularFileProperty getInputFile() {
+                        RegularFileProperty result = project.getObjects().fileProperty();
+                        result.set(new File(getClass().getClassLoader().getResource("puml-files/test.puml").getPath()));
+                        return result;
+                    }
+
+                    @Override
+                    public DirectoryProperty getOutputDirectory() {
+                        DirectoryProperty result = project.getObjects().directoryProperty();
+                        result.set(new File(getClass().getClassLoader().getResource("puml-files").getPath()));
+                        return result;
+                    }
+
+                    @Override
+                    public Property<String> getFileFormat() {
+                        Property<String> property = project.getObjects().property(String.class);
+                        property.set("PNG");
+                        return property;
+                    }
+
+                    @Override
+                    public Property<Boolean> getWithMetadata() {
+                        Property<Boolean> property = project.getObjects().property(Boolean.class);
+                        property.set(false);
+                        return property;
+                    }
+                };
+            }
+        };
+
+        action.execute();
+    }
 }

plantuml-plugin/src/test/resources/puml-files/test.puml

@@ -0,0 +1,6 @@
+@startuml
+
+Bob -> Alice: Test
+Alice --> Bob: return Test
+
+@enduml