Chapter 2: Annotations - @TestPropertySource

@TestPropertySource可以用来覆盖掉来自于系统环境变量、Java系统属性、@PropertySource的属性。

同时@TestPropertySource(properties=...)优先级高于@TestPropertySource(locations=...)。

利用它我们可以很方便的在测试代码里微调、模拟配置（比如修改操作系统目录分隔符、数据源等）。

例子1: 使用Spring Testing工具

我们先使用@PropertySource将一个外部properties文件加载进来，PropertySourceConfig：

@Configuration
@PropertySource("classpath:me/chanjar/annotation/testps/ex1/property-source.properties")
public class PropertySourceConfig {
}

file: property-source.properties
foo=abc

然后我们用@TestPropertySource覆盖了这个property:

@TestPropertySource(properties = { "foo=xyz" ...

最后我们测试了是否覆盖成功（结果是成功的）：

@Test
public void testOverridePropertySource() {
  assertEquals(environment.getProperty("foo"), "xyz");
}

同时我们还对@TestPropertySource做了一些其他的测试，具体情况你可以自己观察。为了方便你观察@TestPropertySource对系统环境变量和Java系统属性的覆盖效果，我们在一开始打印出了它们的值。

源代码TestPropertyTest：

@ContextConfiguration(classes = PropertySourceConfig.class)
@TestPropertySource(
    properties = { "foo=xyz", "bar=uvw", "PATH=aaa", "java.runtime.name=bbb" },
    locations = "classpath:me/chanjar/annotation/testps/ex1/test-property-source.properties"
)
public class TestPropertyTest extends AbstractTestNGSpringContextTests implements EnvironmentAware {
  private Environment environment;
  @Override
  public void setEnvironment(Environment environment) {
    this.environment = environment;
    Map<String, Object> systemEnvironment = ((ConfigurableEnvironment) environment).getSystemEnvironment();
    System.out.println("=== System Environment ===");
    System.out.println(getMapString(systemEnvironment));
    System.out.println();
    System.out.println("=== Java System Properties ===");
    Map<String, Object> systemProperties = ((ConfigurableEnvironment) environment).getSystemProperties();
    System.out.println(getMapString(systemProperties));
  }
  @Test
  public void testOverridePropertySource() {
    assertEquals(environment.getProperty("foo"), "xyz");
  }
  @Test
  public void testOverrideSystemEnvironment() {
    assertEquals(environment.getProperty("PATH"), "aaa");
  }
  @Test
  public void testOverrideJavaSystemProperties() {
    assertEquals(environment.getProperty("java.runtime.name"), "bbb");
  }
  @Test
  public void testInlineTestPropertyOverrideResourceLocationTestProperty() {
    assertEquals(environment.getProperty("bar"), "uvw");
  }
  private String getMapString(Map<String, Object> map) {
    return String.join("\n",
        map.keySet().stream().map(k -> k + "=" + map.get(k)).collect(toList())
    );
  }
}

例子2: 使用Spring Boot Testing工具

@TestPropertySource也可以和@SpringBootTest一起使用。

源代码见TestPropertyTest：

@SpringBootTest(classes = PropertySourceConfig.class)
@TestPropertySource(
    properties = { "foo=xyz", "bar=uvw", "PATH=aaa", "java.runtime.name=bbb" },
    locations = "classpath:me/chanjar/annotation/testps/ex1/test-property-source.properties"
)
public class TestPropertyTest extends AbstractTestNGSpringContextTests implements EnvironmentAware {
  // ... 
}

参考文档

• Spring Framework Testing
• Spring Boot Testing
• Context configuration with test property sources