BROKEN: Add simple tests for ClassLoaderPlus

Unfortunately, the ClassLoaderPlus pollutes the current thread context
class loader, so we either need to change that, or clear it out between
tests. See next commit...

Author: ctrueden

src/test/java/org/scijava/launcher/ClassLoaderPlusTest.java

@@ -0,0 +1,76 @@
+package org.scijava.launcher;
+
+import org.junit.jupiter.api.Test;
+
+import java.io.File;
+import java.lang.reflect.Method;
+import java.net.URLClassLoader;
+import java.nio.file.Paths;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assumptions.assumeTrue;
+
+/**
+ * Tests {@link ClassLoaderPlus}.
+ *
+ * @author Curtis Rueden
+ */
+public class ClassLoaderPlusTest {
+
+	/** Tests {@link ClassLoaderPlus#get}. */
+	@Test
+	public void testGet() throws Exception {
+		File jarFile = Paths.get("src", "test", "resources", "greet.jar").toFile();
+		assumeTrue(jarFile.isFile());
+		URLClassLoader greetLoader = ClassLoaderPlus.get(null, jarFile);
+		assertNotNull(greetLoader);
+		Class<?> greetClass = greetLoader.loadClass("com.example.greet.Greet");
+		assertNotNull(greetClass);
+		assertEquals("com.example.greet.Greet", greetClass.getName());
+	}
+
+	@Test
+	public void testGetFailure() throws Exception {
+		File jarFile = Paths.get("src", "test", "resources", "ask.jar").toFile();
+		assumeTrue(jarFile.isFile());
+		URLClassLoader askLoader = ClassLoaderPlus.get(null, jarFile);
+		assertNotNull(askLoader);
+		Class<?> askClass = askLoader.loadClass("com.example.ask.Ask");
+		assertNotNull(askClass);
+		Exception expected = null;
+		Object value = null;
+		try {
+			value = askClass.getMethod("question").invoke(null);
+		}
+		catch (Exception e) {
+			expected = e;
+			assertEquals(
+				"java.lang.NoClassDefFoundError: com/example/greet/Greet",
+				e.getCause().toString()
+			);
+		}
+		if (expected == null) fail("Expected exception but got value: " + value);
+	}
+
+	/** Tests {@link ClassLoaderPlus#getRecursively}. */
+	@Test
+	public void testGetRecursively() throws Exception {
+		File jarDir = Paths.get("src", "test", "resources").toFile();
+		assumeTrue(jarDir.isDirectory());
+		URLClassLoader classLoader = ClassLoaderPlus.getRecursively(null, true, jarDir);
+		assertNotNull(classLoader);
+		Class<?> askClass = classLoader.loadClass("com.example.ask.Ask");
+		Method questionMethod = askClass.getMethod("question()");
+		Object question = questionMethod.invoke(null);
+		assertEquals("Hello! How are you?", question);
+	}
+
+	/** Tests {@link ClassLoaderPlus#getRecursively} failure cases. */
+	@Test
+	public void testGetRecursivelyFailure() throws Exception {
+		File jarDir = Paths.get("src", "main", "java").toFile();
+		assumeTrue(jarDir.isDirectory());
+		URLClassLoader classLoader = ClassLoaderPlus.getRecursively(null, true, jarDir);
+		assertNull(classLoader);
+	}
+}