Add JarReader unit test for future PR

.gitignore

@@ -1,5 +1,6 @@
 *.java~
 build
 .gradle
+bin/
 out/
 .idea

RSTALanguageSupport/src/test/java/org/fife/rsta/ac/java/JarReaderTest.java

@@ -0,0 +1,61 @@
+/*
+ * This library is distributed under a modified BSD license.  See the included
+ * RSTALanguageSupport.License.txt file for details.
+ */
+package org.fife.rsta.ac.java;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+import java.io.IOException;
+import java.util.List;
+
+import org.fife.rsta.ac.java.buildpath.LibraryInfo;
+import org.fife.rsta.ac.java.classreader.ClassFile;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+
+/**
+ * Unit tests for the {@code JarReader} class.
+ */
+public class JarReaderTest {
+
+    @Test
+    void testGetClassesWithNamesStartingWith_noMatches() throws IOException {
+
+        PackageMapNode packageMap = new PackageMapNode();
+
+        LibraryInfo mockInfo = Mockito.mock(LibraryInfo.class);
+        doReturn(System.currentTimeMillis()).when(mockInfo).getLastModified();
+        doReturn(packageMap).when(mockInfo).createPackageMap();
+
+        JarReader reader = new JarReader(mockInfo);
+        assertEquals(0, reader.getClassesWithNamesStartingWith("Foo").size());
+    }
+
+    @Test
+    void testGetClassesWithNamesStartingWith_matches() throws IOException {
+
+        PackageMapNode packageMap = new PackageMapNode();
+        packageMap.add("com/test/Apple.class");
+        packageMap.add("com/test/Banana.class");
+        packageMap.add("com/test/Foo.class");
+        packageMap.add("com/test/FooBar.class");
+        packageMap.add("com/test/Xyz.class");
+
+        LibraryInfo mockInfo = Mockito.mock(LibraryInfo.class);
+        doReturn(System.currentTimeMillis()).when(mockInfo).getLastModified();
+        doReturn(packageMap).when(mockInfo).createPackageMap();
+        when(mockInfo.createClassFile(anyString())).thenAnswer(input -> {
+            ClassFile cf = Mockito.mock(ClassFile.class);
+            doReturn(input.getArgument(0)).when(cf).getClassName(anyBoolean());
+            return cf;
+        });
+
+        JarReader reader = new JarReader(mockInfo);
+        List<ClassFile> actual = reader.getClassesWithNamesStartingWith("Foo");
+        assertEquals(2, actual.size());
+        assertEquals("com/test/Foo.class", actual.get(0).getClassName(true));
+        assertEquals("com/test/FooBar.class", actual.get(1).getClassName(true));
+    }
+}