Issue #1: Added unit tests for ImageFileFilter.

pom.xml

@@ -300,6 +300,12 @@
             <version>4.12</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <version>2.3.7</version>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>ch.qos.logback</groupId>
             <artifactId>logback-classic</artifactId>

src/test/java/net/sf/javaanpr/gui/tools/ImageFileFilterTest.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2013 JavaANPR contributors
+ * Copyright 2006 Ondrej Martinsky
+ * Licensed under the Educational Community License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.osedu.org/licenses/ECL-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an "AS IS"
+ * BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package net.sf.javaanpr.gui.tools;
+
+import org.junit.Test;
+
+import java.io.File;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.*;
+
+public class ImageFileFilterTest {
+    @Test
+    public void testAcceptsJpgFileName() {
+        assertTrue(ImageFileFilter.accept("some name.jpg"));
+    }
+
+    @Test
+    public void testAcceptsBmpFileName() {
+        assertTrue(ImageFileFilter.accept("some name.bmp"));
+    }
+
+    @Test
+    public void testAcceptsGifFileName() {
+        assertTrue(ImageFileFilter.accept("some name.gif"));
+    }
+
+    @Test
+    public void testAcceptsPngFileName() {
+        assertTrue(ImageFileFilter.accept("some name.png"));
+    }
+
+    @Test
+    public void testDoesNotAcceptFileNameWithoutExtension() {
+        assertFalse(ImageFileFilter.accept("some name"));
+    }
+
+    @Test
+    public void testDoesNotAcceptFileNameWithIncorrectExtension() {
+        assertFalse(ImageFileFilter.accept("some name.txt"));
+    }
+
+    @Test
+    public void testAcceptsDirectory() {
+        File mockedFile = mock(File.class);
+        when(mockedFile.isDirectory()).thenReturn(true);
+        assertTrue(new ImageFileFilter().accept(mockedFile));
+    }
+}