}

    public static Properties getBuildProperties() {
        Properties properties = new Properties();

        try (InputStream resourceAsStream =
                MavenCli.class.getResourceAsStream("/org/apache/maven/messages/build.properties")) {

            if (resourceAsStream != null) {
                properties.load(resourceAsStream);
            }

                    InputStream is = resource.openStream();
                    final Properties properties = new Properties();
                    if (is != null) {
                        try (InputStream in = is) {
                            properties.load(in);
                        }
                    }
                    String impl = properties.getProperty(slf4jBinding);
                    if (impl != null) {

        Map<String, String> properties = new HashMap<>();
        properties.put(ArtifactProperties.TYPE, id);
        properties.put(ArtifactProperties.LANGUAGE, language.id());
        properties.put(MavenArtifactProperties.INCLUDES_DEPENDENCIES, Boolean.toString(includesDependencies));
        properties.put(
                MavenArtifactProperties.CONSTITUTES_BUILD_PATH,

     * where the property value is defined.
     */
    enum Source {
        /**
         * Maven system properties. These properties are evaluated very early during the boot process,
         * typically set by Maven itself and flagged as readOnly=true or by users via maven-system.properties files.
         * System properties are initialized before the build starts and are available throughout the entire Maven

          "unit": "none"
        },
        "overrides": [
          {
            "matcher": {
              "id": "byName",
              "options": "S3 Errors"
            },
            "properties": [
              {
                "id": "color",
                "value": {
                  "fixedColor": "light-red",
                  "mode": "fixed"
                }
              }

     * variable lookup.
     *
     * @param props The properties to add the environment variables to, may be {@code null}.
     */
    public static void addEnvVars(Properties props) {
        if (props != null) {
            if (envVars == null) {
                Properties tmp = new Properties();
                boolean caseSensitive = !Os.IS_WINDOWS;

        }

        return this;
    }

    @Override
    public Properties getSystemProperties() {
        if (systemProperties == null) {
            systemProperties = new Properties();
        }

        return systemProperties;
    }

    @Override
    public DefaultModelBuildingRequest setSystemProperties(Properties systemProperties) {
        if (systemProperties != null) {

            entry.setValue(entry.getValue() + "x");
        }
        Object o21 = properties.get(KEY1);
        assertEquals(VALUE1 + "x", o21);

        baos = new ByteArrayOutputStream();
        properties.save(baos);

        properties = new MavenProperties();
        properties.load(new ByteArrayInputStream(baos.toByteArray()));
        Object o2 = properties.get(KEY1);

+-----+
${maven.home}
     |
     +--- maven.properties
+-----+

* Group configuration

 As far as properties go for an entire build the maven.properties could be placed at
 the top of the group but I'm not really sure how this might work. There could probably
 also be a directory for plugins.xml and maven.properties.

* Project configuration

        Object value = ee.evaluate("${" + key + "}");

        assertEquals(checkValue, value);
    }

    @Test
    public void testValueExtractionFromSystemPropertiesWithMissingProject() throws Exception {
        String sysprop = "PPEET_sysprop1";

        Properties executionProperties = new Properties();