@Test
  void testEmptyCache() {
    MaterializedViewsCache emptyCache = new MaterializedViewsCache();

    ASTNode any = (ASTNode) ParseDriver.adaptor.create(HiveParser.Identifier, "any");

    assertThat(emptyCache.get(any).isEmpty(), is(true));
    assertThat(emptyCache.isEmpty(), is(true));
    assertThat(emptyCache.values().isEmpty(), is(true));
  }
Functional and parallel execution tests for {@link MaterializedViewsCache}.
Parallel execution test is disabled by default.
ql/src/test/org/apache/hadoop/hive/ql/metadata/TestMaterializedViewsCache.java