Package org.junit.contrib.java.lang.system

Class ProvideSystemProperty

java.lang.Object
org.junit.rules.ExternalResource
org.junit.contrib.java.lang.system.ProvideSystemProperty
All Implemented Interfaces:
org.junit.rules.TestRule
public class ProvideSystemProperty extends org.junit.rules.ExternalResource
The ProvideSystemProperty rule provides an arbitrary value for a system property to a test. After the test the original value is restored. You can ensure that a property is not set by providing null (or using ClearSystemProperties).

Let's assume the system property MyProperty is not set and the system property OtherProperty has the value OtherValue. Now run the test 

   public void MyTest {
     @Rule
     public final ProvideSystemProperty provideSystemProperty
       = new ProvideSystemProperty("MyProperty", "MyValue")
         .and("OtherProperty", null);

     @Test
     public void overridesProperty() {
       assertEquals("MyValue", System.getProperty("MyProperty"));
     }

     @Test
     public void deletesProperty() {
       assertNull(System.getProperty("OtherProperty"));
     }
   }
Both tests succeed and after the tests, the system property MyProperty is not set and the system property OtherProperty has the value OtherValue.

You can use a properties file to supply properties for the ProvideSystemProperty rule. The file can be from the file system or the class path. In the first case use 

 @Rule
 public final ProvideSystemProperty properties = ProvideSystemProperty
                .fromFile("/home/myself/example.properties");
and in the second case use 
 @Rule
 public final ProvideSystemProperty properties = ProvideSystemProperty
                .fromResource("example.properties");

Set property for a single test

If you want to set a property for a single test then you can use RestoreSystemProperties along with System.setProperty(String, String). 

 @Rule
 public final TestRule restoreSystemProperties
   = new RestoreSystemProperties();

 @Test
 public void test() {
   System.setProperty("YourProperty", "YourValue");
   ...
 }

  • Field Details

  • Constructor Details

  • Method Details

    • fromFile

      public static ProvideSystemProperty fromFile(String name)

    • fromResource

      public static ProvideSystemProperty fromResource(String name)

    • fromInputStream

      private static ProvideSystemProperty fromInputStream(InputStream is) throws IOException
      Throws:
      IOException

    • setProperty

      @Deprecated public void setProperty(String name, String value)
      Deprecated.
      Please use RestoreSystemProperties along with System.setProperty(String, String).
      Sets the property with the name to the specified value. After the test the rule restores the value of the property at the point of setting it.

      This method is deprecated. If you're still using it, please replace your current code 

       @Rule
 public final ProvideSystemProperty provideSystemProperty = new ProvideSystemProperty();

 @Test
 public void test() {
   provideSystemProperty.setProperty("YourProperty", "YourValue");
   ...
 }
      with this code: 
       @Rule
 public final TestRule restoreSystemProperties = new RestoreSystemProperties();

 @Test
 public void test() {
   System.setProperty("YourProperty", "YourValue");
   ...
 }
      Parameters:
      name - the name of the property.
      value - the new value of the property.
      Since:
      1.6.0

    • and

      public ProvideSystemProperty and(String name, String value)

    • addProperty

      private void addProperty(String name, String value)

    • before

      protected void before() throws Throwable
      Overrides:
      before in class org.junit.rules.ExternalResource
      Throws:
      Throwable

    • setProperties

      private void setProperties()

    • after

      protected void after()
      Overrides:
      after in class org.junit.rules.ExternalResource