content: /*
   * 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.asterix.test.om.typecomputer;
  
  import static org.mockito.Mockito.mock;
  import static org.mockito.Mockito.when;
  
  import java.lang.reflect.Field;
  import java.lang.reflect.Modifier;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Set;
  
  import org.apache.asterix.om.typecomputer.base.IResultTypeComputer;
  import org.apache.asterix.om.typecomputer.impl.BooleanOnlyTypeComputer;
  import org.apache.asterix.om.typecomputer.impl.BooleanOrMissingTypeComputer;
  import org.apache.asterix.om.typecomputer.impl.ClosedRecordConstructorResultType;
  import org.apache.asterix.om.typecomputer.impl.DoubleIfTypeComputer;
  import org.apache.asterix.om.typecomputer.impl.InjectFailureTypeComputer;
  import org.apache.asterix.om.typecomputer.impl.LocalAvgTypeComputer;
  import org.apache.asterix.om.typecomputer.impl.LocalMedianTypeComputer;
  import org.apache.asterix.om.typecomputer.impl.LocalSingleVarStatisticsTypeComputer;
  import org.apache.asterix.om.typecomputer.impl.NullableDoubleTypeComputer;
  import org.apache.asterix.om.typecomputer.impl.OpenRecordConstructorResultType;
  import org.apache.asterix.om.typecomputer.impl.RecordAddFieldsTypeComputer;
  import org.apache.asterix.om.typecomputer.impl.RecordMergeTypeComputer;
  import org.apache.asterix.om.typecomputer.impl.RecordRemoveFieldsTypeComputer;
  import org.apache.asterix.om.typecomputer.impl.ToObjectVarStrTypeComputer;
  import org.apache.asterix.om.types.ATypeTag;
  import org.apache.asterix.om.types.AUnionType;
  import org.apache.asterix.om.types.BuiltinType;
  import org.apache.asterix.om.types.IAType;
  import org.apache.commons.lang3.mutable.Mutable;
  import org.apache.commons.lang3.mutable.MutableObject;
  import org.apache.hyracks.algebricks.core.algebra.base.ILogicalExpression;
  import org.apache.hyracks.algebricks.core.algebra.expressions.AbstractFunctionCallExpression;
  import org.apache.hyracks.algebricks.core.algebra.expressions.IVariableTypeEnvironment;
  import org.apache.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
  import org.apache.hyracks.algebricks.core.algebra.metadata.IMetadataProvider;
  import org.apache.logging.log4j.Level;
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  import org.junit.Assert;
  import org.junit.Test;
  import org.junit.runner.RunWith;
  import org.junit.runners.Parameterized;
  import org.junit.runners.Parameterized.Parameter;
  import org.junit.runners.Parameterized.Parameters;
  import org.reflections.Reflections;
  import org.reflections.scanners.SubTypesScanner;
  
  /**
   * This test passes a number of arguments to the type computers, all arguments of type "any", and ensures that
   * each computer handles the "any" type properly. The expected behavior for each type computer is to return "any",
   * "nullable" or "missable" type result.
   *
   * Things to note:
   * - The function passes 6 "any" arguments because, as of now, no function that we have has more than 6 arguments.
   * - Some functions have a different behavior with "any" value, those will be added to an exception list.
   */
  
  @RunWith(Parameterized.class)
  public class TypeComputerTest {
  
      private static final Logger LOGGER = LogManager.getLogger();
  
      // Number of arguments to create and pass to each type computer
      private static final int NUM_OF_ARGS = 6;
  
      // type computers that have a different behavior when handling "any" type
      private static Set<String> differentBehaviorFunctions = new HashSet<>();
  
      // Test parameters
      @Parameter
      public String testName;
  
      @Parameter(1)
      public Class<? extends IResultTypeComputer> clazz;
  
      @Parameters(name = "TypeComputerTest {index}: {0}")
      public static Collection<Object[]> tests() {
  
          // Do any needed preparations once
          prepare();
  
          // Prepare tests
          List<Object[]> tests = new ArrayList<>();
  
          // Tests all usual type computers.
          Reflections reflections = new Reflections("org.apache.asterix.om.typecomputer", new SubTypesScanner(false));
          Set<Class<? extends IResultTypeComputer>> classes = reflections.getSubTypesOf(IResultTypeComputer.class);
  
          for (Class<? extends IResultTypeComputer> clazz : classes) {
              if (Modifier.isAbstract(clazz.getModifiers())) {
                  LOGGER.log(Level.INFO, "Excluding " + clazz.getSimpleName() + " (Abstract class)");
                  continue;
              }
  
              if (differentBehaviorFunctions.contains(clazz.getSimpleName())) {
                  LOGGER.log(Level.INFO, "Excluding " + clazz.getSimpleName() + " (Special behavior)");
                  continue;
              }
  
              tests.add(new Object[] { clazz.getSimpleName(), clazz });
          }
  
          return tests;
      }
  
      /**
       * Test return types should be either "any", "missable" or "nullable"
       *
       * @throws Exception Exception
       */
      @Test
      public void test() throws Exception {
  
          // Type environment and metadata provider
          IVariableTypeEnvironment typeEnv = mock(IVariableTypeEnvironment.class);
          IMetadataProvider metadataProvider = mock(IMetadataProvider.class);
  
          // Arguments all of type "any"
          List<Mutable<ILogicalExpression>> sixArgs = createArgs(typeEnv);
  
          // Mocks function identifier
          FunctionIdentifier functionIdentifier = mock(FunctionIdentifier.class);
          when(functionIdentifier.getName()).thenReturn("testFunction");
  
          // Mocks function expression.
          AbstractFunctionCallExpression functionCallExpression = mock(AbstractFunctionCallExpression.class);
          when(functionCallExpression.getFunctionIdentifier()).thenReturn(functionIdentifier);
  
          // Sets up required/actual types of the mocked expression.
          Object[] opaqueParameters = new Object[] { BuiltinType.ANY, BuiltinType.ANY };
          when(functionCallExpression.getOpaqueParameters()).thenReturn(opaqueParameters);
  
          // Tests the return type. It should be either ANY or NULLABLE/MISSABLE.
          IResultTypeComputer instance;
          IAType resultType;
          Field[] fields = clazz.getFields();
  
          for (Field field : fields) {
  
              // Ensure the field is one of the instances of the class
              if (field.getType().equals(clazz)) {
                  LOGGER.log(Level.INFO, "Testing " + clazz.getSimpleName() + ": " + field.getName());
                  instance = (IResultTypeComputer) field.get(null);
                  when(functionCallExpression.getArguments()).thenReturn(argsFor(instance, sixArgs));
                  resultType = instance.computeType(functionCallExpression, typeEnv, metadataProvider);
                  ATypeTag typeTag = resultType.getTypeTag();
  
                  // Result should be ANY, Missable or Nullable
                  Assert.assertTrue(typeTag == ATypeTag.ANY || (typeTag == ATypeTag.UNION
                          && (((AUnionType) resultType).isNullableType() || ((AUnionType) resultType).isMissableType())));
              }
          }
      }
  
      private static List<Mutable<ILogicalExpression>> argsFor(IResultTypeComputer typeComputer,
              List<Mutable<ILogicalExpression>> sixArgs) {
          if (typeComputer.getClass() == DoubleIfTypeComputer.class) {
              return sixArgs.subList(0, 2);
          }
          return sixArgs;
      }
  
      public static void prepare() {
          // Add to exception list for computers having a different behavior for "any" type
          addComputersBehavingDifferently();
      }
  
      /**
       * Adds the type computers that have a different behavior for "any" type.
       */
      private static void addComputersBehavingDifferently() {
          differentBehaviorFunctions.add(InjectFailureTypeComputer.class.getSimpleName());
          differentBehaviorFunctions.add(RecordAddFieldsTypeComputer.class.getSimpleName());
          differentBehaviorFunctions.add(OpenRecordConstructorResultType.class.getSimpleName());
          differentBehaviorFunctions.add(RecordRemoveFieldsTypeComputer.class.getSimpleName());
          differentBehaviorFunctions.add(ClosedRecordConstructorResultType.class.getSimpleName());
          differentBehaviorFunctions.add(LocalAvgTypeComputer.class.getSimpleName());
          differentBehaviorFunctions.add(LocalMedianTypeComputer.class.getSimpleName());
          differentBehaviorFunctions.add(BooleanOnlyTypeComputer.class.getSimpleName());
          //        differentBehaviorFunctions.add("AMissingTypeComputer"); // TODO What type computer is this?
          differentBehaviorFunctions.add(NullableDoubleTypeComputer.class.getSimpleName());
          differentBehaviorFunctions.add(RecordMergeTypeComputer.class.getSimpleName());
          differentBehaviorFunctions.add(BooleanOrMissingTypeComputer.class.getSimpleName());
          differentBehaviorFunctions.add(LocalSingleVarStatisticsTypeComputer.class.getSimpleName());
          differentBehaviorFunctions.add(ToObjectVarStrTypeComputer.class.getSimpleName());
      }
  
      /**
       * Creates expressions matching the number passed as an argument. Variable type environment is set for all those
       * expressions to be of type "any".
       *
       * @param typeEnv Type environment
       * @return a list holding the created expressions
       * @throws Exception Exception
       */
      private static List<Mutable<ILogicalExpression>> createArgs(IVariableTypeEnvironment typeEnv) throws Exception {
  
          List<Mutable<ILogicalExpression>> arguments = new ArrayList<>();
  
          for (int i = 0; i < NUM_OF_ARGS; ++i) {
              ILogicalExpression argument = mock(ILogicalExpression.class);
              arguments.add(new MutableObject<>(argument));
              when(typeEnv.getType(argument)).thenReturn(BuiltinType.ANY);
          }
  
          return arguments;
      }
  }
  