Add a very basic Swing unit test

.github/workflows/gradle.yml

@@ -23,6 +23,8 @@ jobs:
       run: chmod +x gradlew
     - name: Install docs dependencies
       run: pip3 install -r docs/requirements.txt -U  
+    - name: Install Xvfb server for UI tests
+      run: sudo apt install xvfb
     - name: Read version from gradle.properties
       id: read_version
       uses: christian-draeger/read-properties@1.0.0
@@ -33,8 +35,12 @@ jobs:
     # Compile the code, run unit tests, upload code coverage results.
     - name: Compile Java code
       run: ./gradlew compileJava
+    - name: Start Xvfb
+      run: /usr/bin/Xvfb -ac :42 &
     - name: Run unit tests
-      run: ./gradlew check
+      run: DISPLAY=42 ./gradlew check
+    - name: Kill VNC
+      run: vncserver -kill :42
     - name: Codecov
       uses: codecov/codecov-action@v1.0.5
       with:

build.gradle.kts

@@ -22,6 +22,8 @@ dependencies {
     compileOnly("com.google.gwt:gwt-user:2.8.2")
     implementation("javax.help:javahelp:2.0.05")
     testImplementation("junit:junit:4.12")
+    testCompile("org.assertj:assertj-core:3.11.1")
+    testCompile("org.assertj:assertj-swing:3.9.2")
 }
 
 application {

src/main/java/org/edumips64/Main.java

@@ -55,6 +55,9 @@
 
 public class Main {
 
+  // Elements that are public for unit tests.
+  public JFrame mainFrame;
+
   private CPU cpu;
   // The last created CPU Worker. Necessary for the Stop menu item.
   private CPUSwingWorker cpuWorker;
@@ -67,7 +70,6 @@ public class Main {
   private ConfigStore configStore;
   private JFileChooser jfc;
 
-  private JFrame mainFrame;
   private JMenuItem open;
   private JMenuItem reset;
   private JMenuItem exit;
@@ -195,53 +197,7 @@ public static void main(String args[]) {
     System.setProperty("java.util.logging.SimpleFormatter.format", "%1$tm%1$td %1$tH:%1$tM:%1$tS %4$s %2$s %5$s%6$s%n");
 
     Main.showVersion();
-
-    // Creating the main JFrame
-    JFrame.setDefaultLookAndFeelDecorated(true);
-    JDialog.setDefaultLookAndFeelDecorated(true);
-    mm.mainFrame = new JFrame();
-    mm.mainFrame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
-    // Maximizing the application
-    Insets screenInsets = mm.mainFrame.getToolkit().getScreenInsets(mm.mainFrame.getGraphicsConfiguration());
-    Rectangle screenSize = mm.mainFrame.getGraphicsConfiguration().getBounds();
-    Rectangle maxBounds = new Rectangle(screenInsets.left + screenSize.x,
-                                        screenInsets.top + screenSize.y,
-                                        screenSize.x + screenSize.width - screenInsets.right - screenInsets.left,
-                                        screenSize.y + screenSize.height - screenInsets.bottom - screenInsets.top);
-    mm.mainFrame.setMaximizedBounds(maxBounds);
-    mm.mainFrame.setBounds(maxBounds);
-
-    mm.mainFrame.setLocation(0, 0);
     mm.init();
-    mm.mainFrame.setTitle("EduMIPS64 v. " + MetaInfo.VERSION + " - " + CurrentLocale.getString("PROSIM"));
-    mm.mainFrame.setVisible(true);
-    mm.mainFrame.setExtendedState(mm.mainFrame.getExtendedState() | JFrame.MAXIMIZED_BOTH);
-    // Auto-minimze the log window and the I/O window
-    try {
-      mm.ioFrame.setIcon(true);
-    } catch (java.beans.PropertyVetoException ignored) {}
-
-    // Tile windows once the window is maximized.
-    mm.mainFrame.addWindowStateListener(new WindowStateListener() {
-      // Keep track of whether maximization was already done, to prevent unwanted tiling of windows when the main
-      // window is maximized again.
-        private boolean alreadyMaximized = false;
-
-        public void windowStateChanged(WindowEvent event) {
-          if (alreadyMaximized) {
-            return;
-          }
-          boolean isMaximized = (event.getNewState() & Frame.MAXIMIZED_BOTH) == Frame.MAXIMIZED_BOTH;
-          boolean wasMaximized = (event.getOldState() & Frame.MAXIMIZED_BOTH) == Frame.MAXIMIZED_BOTH;
-
-          if (isMaximized && !wasMaximized) {
-            mm.tileWindows();
-            alreadyMaximized = true;
-          }
-        }
-     });
-
-    log.info("Simulator started");
 
     if (parsedArgs.filename != null) {
       mm.resetSimulator(false);
@@ -283,8 +239,13 @@ private void setFileChooserFont(Component[] components) {
   }
 
   public void init() {
+    // Creating the main JFrame
     JFrame.setDefaultLookAndFeelDecorated(true);
     JDialog.setDefaultLookAndFeelDecorated(true);
+    mainFrame = new JFrame();
+    mainFrame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
+
+    log.info("Simulator started");
     LocalFileUtils lfu = new LocalFileUtils();
 
     configStore = new JavaPrefsConfigStore(ConfigStore.defaults);
@@ -453,6 +414,45 @@ public void internalFrameDeiconified(InternalFrameEvent e) {
     codeSupplier = () -> this.code;
 
     changeShownMenuItems(cpu.getStatus());
+
+    // Maximizing the application
+    Insets screenInsets = mainFrame.getToolkit().getScreenInsets(mainFrame.getGraphicsConfiguration());
+    Rectangle screenSize = mainFrame.getGraphicsConfiguration().getBounds();
+    Rectangle maxBounds = new Rectangle(screenInsets.left + screenSize.x,
+                                        screenInsets.top + screenSize.y,
+                                        screenSize.x + screenSize.width - screenInsets.right - screenInsets.left,
+                                        screenSize.y + screenSize.height - screenInsets.bottom - screenInsets.top);
+    mainFrame.setMaximizedBounds(maxBounds);
+    mainFrame.setBounds(maxBounds);
+
+    mainFrame.setLocation(0, 0);
+    mainFrame.setTitle("EduMIPS64 v. " + MetaInfo.VERSION + " - " + CurrentLocale.getString("PROSIM"));
+    mainFrame.setVisible(true);
+    mainFrame.setExtendedState(mainFrame.getExtendedState() | JFrame.MAXIMIZED_BOTH);
+    // Auto-minimze the log window and the I/O window
+    try {
+      ioFrame.setIcon(true);
+    } catch (java.beans.PropertyVetoException ignored) {}
+
+    // Tile windows once the window is maximized.
+    mainFrame.addWindowStateListener(new WindowStateListener() {
+      // Keep track of whether maximization was already done, to prevent unwanted tiling of windows when the main
+      // window is maximized again.
+        private boolean alreadyMaximized = false;
+
+        public void windowStateChanged(WindowEvent event) {
+          if (alreadyMaximized) {
+            return;
+          }
+          boolean isMaximized = (event.getNewState() & Frame.MAXIMIZED_BOTH) == Frame.MAXIMIZED_BOTH;
+          boolean wasMaximized = (event.getOldState() & Frame.MAXIMIZED_BOTH) == Frame.MAXIMIZED_BOTH;
+
+          if (isMaximized && !wasMaximized) {
+            tileWindows();
+            alreadyMaximized = true;
+          }
+        }
+     });
   }
 
   /** Changes the status of running menu items.

src/test/java/org/edumips64/MainTest.java

@@ -0,0 +1,54 @@
+/* MainTest.java
+ *
+ * Tests for the Main class of EduMIPS64.
+ *
+ * (c) 2020 Andrea Spadaccini
+ *
+ * This file is part of the EduMIPS64 project, and is released under the GNU
+ * General Public License.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+package org.edumips64;
+
+import org.junit.*;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+import org.assertj.swing.edt.GuiActionRunner;
+import org.assertj.swing.fixture.FrameFixture;
+
+@RunWith(JUnit4.class)
+public class MainTest {
+    private FrameFixture window;
+
+    @Before
+    public void setUp() {
+        Main main = GuiActionRunner.execute(() -> new Main());
+        main.init();
+        window = new FrameFixture(main.mainFrame);
+        window.show();
+    }
+
+    @Test
+    public void shouldBePossibleToExit() {
+        window.menuItemWithPath("File", "Exit").click();
+    }
+
+    @After
+    public void tearDown() {
+        window.cleanUp();
+    }
+}