Fix set and remove method signatures

system-stubs-core/src/main/java/uk/org/webcompere/systemstubs/properties/SystemPropertiesImpl.java

@@ -16,7 +16,7 @@
  * that will be applied to the system to be set before the stubbing is triggered.
  */
 public class SystemPropertiesImpl<T extends SystemPropertiesImpl<T>> extends SingularTestResource
-    implements NameValuePairSetter<SystemPropertiesImpl<T>> {
+    implements NameValuePairSetter<T> {
     private Properties originalProperties;
     private Properties properties;
 
@@ -70,12 +70,13 @@ public SystemPropertiesImpl(String name, String value, String... nameValues) {
      * @since 1.0.0
      */
     @Override
-    public SystemPropertiesImpl<T> set(String name, String value) {
+    @SuppressWarnings("unchecked")
+    public T set(String name, String value) {
         properties.setProperty(name, value);
         if (isActive()) {
             System.setProperty(name, value);
         }
-        return this;
+        return (T) this;
     }
 
     /**
@@ -86,12 +87,13 @@ public SystemPropertiesImpl<T> set(String name, String value) {
      * @since 2.1.5
      */
     @Override
-    public SystemPropertiesImpl<T> remove(String name) {
+    @SuppressWarnings("unchecked")
+    public T remove(String name) {
         propertiesToRemove.add(name);
         if (isActive()) {
             System.getProperties().remove(name);
         }
-        return this;
+        return (T) this;
     }
 
     @Override

system-stubs-core/src/test/java/uk/org/webcompere/systemstubs/properties/SystemPropertiesTest.java

@@ -147,8 +147,7 @@ void settingAfterPreDeleteAlsoWorks() throws Exception {
             properties.set("bar", "h");
             assertThat(System.getProperty("bar")).isEqualTo("h");
 
-            SystemProperties nested = new SystemProperties();
-            nested.remove("bar");
+            SystemProperties nested = new SystemProperties().remove("bar");
             nested.execute(() -> {
                 nested.set("bar", "bong");
                 assertThat(System.getProperty("bar")).isEqualTo("bong");

system-stubs-junit4/src/main/java/uk/org/webcompere/systemstubs/rules/SystemPropertiesRule.java

@@ -3,7 +3,6 @@
 import uk.org.webcompere.systemstubs.properties.SystemPropertiesImpl;
 import uk.org.webcompere.systemstubs.rules.internal.SystemStubTestRule;
 
-import java.util.Map;
 import java.util.Properties;
 
 /**
@@ -30,12 +29,4 @@ public SystemPropertiesRule(Properties properties) {
     public SystemPropertiesRule(String name, String value, String... nameValues) {
         super(name, value, nameValues);
     }
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public SystemPropertiesRule set(Map<Object, Object> properties) {
-        return (SystemPropertiesRule)super.set(properties);
-    }
 }

system-stubs-jupiter/src/test/java/uk/org/webcompere/systemstubs/jupiter/SystemStubsExtensionTest.java

@@ -43,6 +43,29 @@ void method3_hasCleanPropertiesAndEnvironment() {
         }
     }
 
+    @ExtendWith(SystemStubsExtension.class)
+    @Nested
+    class SystemPropertiesAsParentClass {
+
+        @SystemStub
+        private SystemProperties systemProperties = new WithDefaultsSystemProperties()
+            .set("key1", "value3");
+
+        @Test
+        void defaultValuesAreSet() {
+            assertThat(System.getProperty("key1")).isEqualTo("value3");
+            assertThat(System.getProperty("key2")).isEqualTo("value2");
+        }
+    }
+
+    private static class WithDefaultsSystemProperties extends SystemProperties {
+
+        WithDefaultsSystemProperties() {
+            super("key1", "value1");
+            this.set("key2", "value2");
+        }
+    }
+
     @ExtendWith(SystemStubsExtension.class)
     @Nested
     class FieldWithoutAnnotation {