Add CLI tests for the language options.

jplag/src/test/java/jplag/cli/LanguageOptionTest.java

@@ -0,0 +1,39 @@
+package jplag.cli;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.contrib.java.lang.system.ExpectedSystemExit;
+
+import jplag.CommandLineArgument;
+import jplag.options.LanguageOption;
+
+public class LanguageOptionTest extends CommandLineInterfaceTest {
+
+    @Rule
+    public final ExpectedSystemExit exit = ExpectedSystemExit.none();
+
+    @Test
+    public void testDefaultLanguage() {
+        buildOptionsFromCLI(CURRENT_DIRECTORY);
+        assertEquals(LanguageOption.getDefault(), options.getLanguageOption());
+    }
+
+    @Test
+    public void testInvalidLanguage() {
+        exit.expectSystemExitWithStatus(1);
+        String argument = buildArgument(CommandLineArgument.LANGUAGE, "Piet");
+        buildOptionsFromCLI(argument, CURRENT_DIRECTORY);
+    }
+
+    @Test
+    public void testValidLanguages() {
+        for (LanguageOption language : LanguageOption.values()) {
+            String argument = buildArgument(CommandLineArgument.LANGUAGE, language.getDisplayName());
+            buildOptionsFromCLI(argument, CURRENT_DIRECTORY);
+            assertEquals(language, options.getLanguageOption());
+        }
+    }
+
+}