Added unit tests and updated README.md

Author: Tobias Stamann

README.md

@@ -224,7 +224,37 @@ public void yourUnitTestWithPassedInElementAndProcessor() {
 
 }
 ```
- 
+
+### Testing generated and compiled classes
+Testing of the generated code can either be done by providing an integration test project or by using Cute to achieve this as part of the compilation test.
+Unfortunately, testing generated code with Cute heavily relies on the Javas reflection api, since generated classes aren't available in your unit test code.
+But it's working flawlessly if your generated classes are implementing precompiled interfaces:
+
+````java
+@Test
+public void blackBoxTest_justCompileCodeAndDoClassTestWithImplementedInterface() {
+    Cute.blackBoxTest().given().noProcessors()
+        .andSourceFiles("/TestClassWithImplementedInterface.java")
+        .whenCompiled()
+        .thenExpectThat()
+        .compilationSucceeds()
+        .andThat()
+            .generatedClass("io.toolisticon.cute.TestClassWithImplementedInterface")
+            .testedSuccessfullyBy(new GeneratedClassesTestForSpecificClass() {
+                @Override
+                public void doTests(Class<?> clazz, CuteClassLoader cuteClassLoader) throws Exception{
+    
+                    SimpleTestInterface unit = (SimpleTestInterface) clazz.getConstructor().newInstance();
+                    MatcherAssert.assertThat(unit.saySomething(), Matchers.is("WHATS UP?"));
+    
+                }
+            })
+        .executeTest();
+}
+````
+
+Consider to prefer integration tests over Cute if no precompiled interface is implemented by the generated classes.
+
 # Projects using this toolkit library
 
 - [Annotation processor toolkit](https://github.com/toolisticon/annotation-processor-toolkit) : Toolkit that allows you to build annotation processors in a more comfortable way

cute/src/test/java/io/toolisticon/cute/CuteTest.java

@@ -1086,4 +1086,23 @@ public void doTests(Class<?> clazz, CuteClassLoader cuteClassLoader) throws Exce
                 .executeTest();
     }
 
+
+    @Test()
+    public void blackBoxTest_justCompileCodeAndDoClassTestWithImplementedInterfaceAndRelationsBetweenClasses() {
+        Cute.blackBoxTest().given().noProcessors()
+                .andSourceFiles("/compiletests/withmultiplerelatedsourcefiles/JustOutput.java", "/compiletests/withmultiplerelatedsourcefiles/TestClassWithImplementedInterface.java")
+                .whenCompiled()
+                .thenExpectThat()
+                .compilationSucceeds()
+                .andThat().generatedClass("io.toolisticon.cute.TestClassWithImplementedInterface").testedSuccessfullyBy(new GeneratedClassesTestForSpecificClass() {
+                    @Override
+                    public void doTests(Class<?> clazz, CuteClassLoader cuteClassLoader) throws Exception{
+
+                        SimpleTestInterface unit = (SimpleTestInterface) clazz.getConstructor().newInstance();
+                        MatcherAssert.assertThat(unit.saySomething(), Matchers.is("WHATS UP???"));
+
+                    }
+                })
+                .executeTest();
+    }
 }

cute/src/test/resources/compiletests/withmultiplerelatedsourcefiles/JustOutput.java

@@ -0,0 +1,8 @@
+package io.toolisticon.cute;
+
+public class JustOutput {
+
+    public static String getString() {
+        return "WHATS UP???";
+    }
+}

cute/src/test/resources/compiletests/withmultiplerelatedsourcefiles/TestClassWithImplementedInterface.java

@@ -0,0 +1,16 @@
+package io.toolisticon.cute;
+
+import io.toolisticon.cute.TestAnnotation;
+import io.toolisticon.cute.testcases.SimpleTestInterface;
+
+/**
+ * Test class for annotation processor tools.
+ */
+@TestAnnotation
+public class TestClassWithImplementedInterface implements SimpleTestInterface {
+
+    @Override
+    public String saySomething() {
+        return JustOutput.getString();
+    }
+}