verify all example-projects can be assembled

DGP can still produce output even when the code cannot be compiled.
To avoid creating invalid examples, add a test.

Author: adam-enko

dokka-integration-tests/gradle/src/testExampleProjects/kotlin/ExampleProjectsTest.kt

@@ -244,6 +244,20 @@ class ExampleProjectsTest {
         }
     }
 
+    @ParameterizedTest
+    @ArgumentsSource(TestCaseProvider::class)
+    fun `test project assemble`(testCase: TestCase) {
+        assumeTrue(testCase.isEnabled)
+
+        testCase.project.runner
+            .addArguments(
+                "assemble",
+                "--stacktrace",
+            )
+            .build {
+                output shouldContain "BUILD SUCCESSFUL"
+            }
+    }
 
     @ParameterizedTest
     @ArgumentsSource(TestCaseProvider::class)

examples/gradle-v2/composite-build-example/build.gradle.kts

@@ -21,3 +21,10 @@ tasks.clean {
         gradle.includedBuild("module-kea").task(":clean"),
     )
 }
+
+tasks.assemble {
+    dependsOn(
+        gradle.includedBuild("module-kakapo").task(":assemble"),
+        gradle.includedBuild("module-kea").task(":assemble"),
+    )
+}