[HUDI-896] Report test coverage by modules & parallelize CI (#1753)

- use codecov flags for each module to report coverage
- parallelize CI jobs for shorter time
- add a testcase for MetricsReporterFactory (to trigger codecov comment)

hudi-client/src/test/java/org/apache/hudi/metrics/TestMetricsReporterFactory.java

@@ -0,0 +1,48 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache 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.apache.org/licenses/LICENSE-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 org.apache.hudi.metrics;
+
+import org.apache.hudi.config.HoodieWriteConfig;
+
+import com.codahale.metrics.MetricRegistry;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.when;
+
+@ExtendWith(MockitoExtension.class)
+public class TestMetricsReporterFactory {
+
+  @Mock
+  HoodieWriteConfig config;
+
+  @Mock
+  MetricRegistry registry;
+
+  @Test
+  public void metricsReporterFactoryShouldReturnReporter() {
+    when(config.getMetricsReporterType()).thenReturn(MetricsReporterType.INMEMORY);
+    MetricsReporter reporter = MetricsReporterFactory.createReporter(config, registry);
+    assertTrue(reporter instanceof InMemoryMetricsReporter);
+  }
+}