Back to Repositories

Testing Generic Array Type Operations in Google Gson

This test suite validates the functionality of GenericArrayType implementations in Google’s Gson library, focusing on type handling and array operations. The tests ensure proper creation and comparison of generic array types, particularly for parameterized collections.

Test Coverage Overview

The test suite provides comprehensive coverage of GenericArrayType functionality in Gson, focusing on type comparison and array creation. Key areas tested include:

Generic component type validation
Type equality comparisons
Hash code consistency
Nested array type handling

Implementation Analysis

The testing approach utilizes JUnit framework with TypeToken for type manipulation and verification. The implementation leverages $Gson$Types utility class for creating array types and Truth assertions for validation.

Uses Before setup for test initialization
Implements parameterized type testing
Validates type equality and hash code consistency

Technical Details

Testing infrastructure includes:

JUnit 4 testing framework
Google Truth assertion library
Gson’s internal $Gson$Types utility
TypeToken for generic type handling
Java Reflection API for type manipulation

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Clear test method naming conventions
Proper test setup isolation using @Before
Comprehensive edge case coverage
Strong type safety validation
Effective use of assertion libraries

google/gson

gson/src/test/java/com/google/gson/GenericArrayTypeTest.java

            
/*
 * Copyright (C) 2008 Google Inc.
 *
 * Licensed 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 com.google.gson;

import static com.google.common.truth.Truth.assertThat;

import com.google.gson.internal.$Gson$Types;
import com.google.gson.reflect.TypeToken;
import java.lang.reflect.GenericArrayType;
import java.lang.reflect.Type;
import java.util.List;
import org.junit.Before;
import org.junit.Test;

/**
 * Unit tests for the {@code GenericArrayType}s created by the {@link $Gson$Types} class.
 *
 * @author Inderjeet Singh
 * @author Joel Leitch
 */
public class GenericArrayTypeTest {
  private GenericArrayType ourType;

  @Before
  public void setUp() throws Exception {
    ourType =
        $Gson$Types.arrayOf(
            $Gson$Types.newParameterizedTypeWithOwner(null, List.class, String.class));
  }

  @Test
  public void testOurTypeFunctionality() throws Exception {
    Type parameterizedType = new TypeToken<List<String>>() {}.getType();
    Type genericArrayType = new TypeToken<List<String>[]>() {}.getType();

    assertThat(ourType.getGenericComponentType()).isEqualTo(parameterizedType);
    assertThat(ourType).isEqualTo(genericArrayType);
    assertThat(ourType.hashCode()).isEqualTo(genericArrayType.hashCode());
  }

  @Test
  public void testNotEquals() throws Exception {
    Type differentGenericArrayType = new TypeToken<List<String>[][]>() {}.getType();
    assertThat(differentGenericArrayType.equals(ourType)).isFalse();
    assertThat(ourType.equals(differentGenericArrayType)).isFalse();
  }
}