Can pass configuration using system properties

For example, one can run:

    mvn test -Dnotifier.anybar.port=1740

to change port used by AnyBar to indicate build status.

src/main/java/fr/jcgay/maven/notifier/ConfigurationParser.java

@@ -9,6 +9,7 @@
 import java.io.InputStream;
 import java.net.MalformedURLException;
 import java.net.URL;
+import java.util.Map;
 import java.util.Properties;
 
 import static fr.jcgay.maven.notifier.ConfigurationParser.ConfigurationProperties.Property.IMPLEMENTATION;
@@ -144,6 +145,13 @@ private static class ConfiguredProperties {
         public Properties properties() {
             Properties result = new Properties();
             result.putAll(properties);
+
+            for (Map.Entry<Object, Object> property : System.getProperties().entrySet()) {
+                if (property.getKey().toString().startsWith("notifier.")) {
+                    result.put(property.getKey(), property.getValue());
+                }
+            }
+
             String overrideImplementation = System.getProperty(NOTIFY_WITH.key());
             if (overrideImplementation != null) {
                 result.put(IMPLEMENTATION.key(), overrideImplementation);

src/test/groovy/fr/jcgay/maven/notifier/ConfigurationParserTest.groovy

@@ -111,4 +111,16 @@ class ConfigurationParserTest {
 
         assertThat(result[IMPLEMENTATION.key()]).isEqualTo('snarl')
     }
+
+    @Test
+    void 'should use configuration passed by system property'() {
+
+        System.setProperty('notifier.anybar.port', '1111')
+        System.setProperty('notifier.anybar.host', 'localhost')
+
+        def result = ConfigurationParser.readProperties(getClass().getResource('/anybar.properties'))
+
+        assertThat result['notifier.anybar.port'] isEqualTo '1111'
+        assertThat result['notifier.anybar.host'] isEqualTo 'localhost'
+    }
 }

src/test/resources/anybar.properties

@@ -0,0 +1,2 @@
+notifier.anybar.port=1738
+notifier.anybar.host=192.168.1.1