Reproduce #41 (#86)

As far as I can tell interface works fine.

build.sbt

@@ -135,4 +135,19 @@ ThisBuild / githubWorkflowPublish := Seq(
   )
 )
 ThisBuild / sonatypeProfileName := "com.github.sbt"
+// So that publishLocal doesn't continuously create new versions
+def versionFmt(out: sbtdynver.GitDescribeOutput): String = {
+  val snapshotSuffix = if
+    (out.isSnapshot()) "-SNAPSHOT"
+  else ""
+    out.ref.dropPrefix + snapshotSuffix
+}
+
+def fallbackVersion(d: java.util.Date): String = s"HEAD-${sbtdynver.DynVer timestamp d}"
+
+ThisBuild / version := dynverGitDescribeOutput.value.mkVersion(versionFmt, fallbackVersion(dynverCurrentDate.value))
+ThisBuild / dynver := {
+  val d = new java.util.Date
+  sbtdynver.DynVer.getGitDescribeOutput(d).mkVersion(versionFmt, fallbackVersion(d))
+}
 Global / onChangedBuildSource := ReloadOnSourceChanges

src/plugin/src/sbt-test/basic/interface-demo/build.sbt

@@ -0,0 +1,4 @@
+name := "test-project"
+libraryDependencies ++= Seq(
+  "com.github.sbt.junit" % "jupiter-interface" % JupiterKeys.jupiterVersion.value % Test
+)

src/plugin/src/sbt-test/basic/interface-demo/project/plugins.sbt

@@ -0,0 +1 @@
+addSbtPlugin("com.github.sbt.junit" % "sbt-jupiter-interface" % sys.props("project.version"))

src/plugin/src/sbt-test/basic/interface-demo/src/test/java/example/ComparableContract.java

@@ -0,0 +1,31 @@
+package example;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public interface ComparableContract<T extends Comparable<T>> extends Testable<T> {
+
+    T createSmallerValue();
+
+    @Test
+    default void returnsZeroWhenComparedToItself() {
+        T value = createValue();
+        assertEquals(0, value.compareTo(value));
+    }
+
+    @Test
+    default void returnsPositiveNumberWhenComparedToSmallerValue() {
+        T value = createValue();
+        T smallerValue = createSmallerValue();
+        assertTrue(value.compareTo(smallerValue) > 0);
+    }
+
+    @Test
+    default void returnsNegativeNumberWhenComparedToLargerValue() {
+        T value = createValue();
+        T smallerValue = createSmallerValue();
+        assertTrue(smallerValue.compareTo(value) < 0);
+    }
+
+}

src/plugin/src/sbt-test/basic/interface-demo/src/test/java/example/EqualsContract.java

@@ -0,0 +1,31 @@
+package example;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public interface EqualsContract<T> extends Testable<T> {
+
+    T createNotEqualValue();
+
+    @Test
+    default void valueEqualsItself() {
+        T value = createValue();
+        assertEquals(value, value);
+    }
+
+    @Test
+    default void valueDoesNotEqualNull() {
+        T value = createValue();
+        assertFalse(value.equals(null));
+    }
+
+    @Test
+    default void valueDoesNotEqualDifferentValue() {
+        T value = createValue();
+        T differentValue = createNotEqualValue();
+        assertNotEquals(value, differentValue);
+        assertNotEquals(differentValue, value);
+    }
+
+}

src/plugin/src/sbt-test/basic/interface-demo/src/test/java/example/StringTests.java

@@ -0,0 +1,20 @@
+package example;
+
+class StringTests implements ComparableContract<String>, EqualsContract<String> {
+
+    @Override
+    public String createValue() {
+        return "banana";
+    }
+
+    @Override
+    public String createSmallerValue() {
+        return "apple"; // 'a' < 'b' in "banana"
+    }
+
+    @Override
+    public String createNotEqualValue() {
+        return "cherry";
+    }
+
+}

src/plugin/src/sbt-test/basic/interface-demo/src/test/java/example/Testable.java

@@ -0,0 +1,5 @@
+package example;
+
+public interface Testable<T> {
+    T createValue();
+}

src/plugin/src/sbt-test/basic/interface-demo/test

@@ -0,0 +1 @@
+> test