add a test for getLanguageByFilename

Signed-off-by: Miguel Molina <miguel@erizocosmi.co>

java/src/test/java/tech/sourced/enry/EnryTest.java

@@ -28,6 +28,15 @@ public class EnryTest {
         );
     }
 
+    @Test
+    public void getLanguageByFilename() {
+        assertGuess(
+                "Maven POM",
+                true,
+                Enry.getLanguageByFilename("pom.xml")
+        );
+    }
+
     @Test
     public void getLanguageByEmacsModeline() {
         String code = "// -*- font:bar;mode:c++ -*-\n" +