diff --git a/fix_test.py b/fix_test.py
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--- /dev/null
+++ b/fix_test.py
@@ -0,0 +1,10 @@
+import re
+
+with open('org.moreunit.core.test/test/org/moreunit/core/config/ModuleTest.java', 'r') as f:
+    content = f.read()
+
+content = content.replace("boolean prepareCalled = false;", "boolean prepareCalled;")
+content = content.replace("boolean cleanCalled = false;", "boolean cleanCalled;")
+
+with open('org.moreunit.core.test/test/org/moreunit/core/config/ModuleTest.java', 'w') as f:
+    f.write(content)
diff --git a/org.moreunit.core.test/test/org/moreunit/core/config/ModuleTest$TestModule.class b/org.moreunit.core.test/test/org/moreunit/core/config/ModuleTest$TestModule.class
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diff --git a/org.moreunit.core.test/test/org/moreunit/core/config/ModuleTest.class b/org.moreunit.core.test/test/org/moreunit/core/config/ModuleTest.class
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index 00000000..cc9cf7b0
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diff --git a/org.moreunit.core.test/test/org/moreunit/core/config/ModuleTest.java b/org.moreunit.core.test/test/org/moreunit/core/config/ModuleTest.java
new file mode 100644
index 00000000..2b211b5b
--- /dev/null
+++ b/org.moreunit.core.test/test/org/moreunit/core/config/ModuleTest.java
@@ -0,0 +1,188 @@
+package org.moreunit.core.config;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.ArgumentMatchers.startsWith;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.inOrder;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.InOrder;
+import org.moreunit.core.log.Logger;
+import org.osgi.framework.BundleContext;
+
+public class ModuleTest
+{
+    private Logger logger;
+    private BundleContext context;
+    private TestModule module;
+
+    @Before
+    public void setUp()
+    {
+        logger = mock(Logger.class);
+        context = mock(BundleContext.class);
+        TestModule.instance = null;
+        module = new TestModule(false, logger);
+    }
+
+    @Test
+    public void start_should_prepare_and_start_registered_services()
+    {
+        Service service1 = mock(Service.class);
+        Service service2 = mock(Service.class);
+
+        module.addService(service1);
+        module.addService(service2);
+
+        module.start(context);
+
+        assertThat(module.prepareCalled).isTrue();
+        assertThat(module.getContext()).isEqualTo(context);
+
+        InOrder inOrder = inOrder(service1, service2);
+        inOrder.verify(service1).start();
+        inOrder.verify(service2).start();
+    }
+
+    @Test
+    public void stop_should_stop_services_in_reverse_order_and_clean()
+    {
+        Service service1 = mock(Service.class);
+        Service service2 = mock(Service.class);
+
+        module.addService(service1);
+        module.addService(service2);
+
+        module.start(context);
+        module.stop();
+
+        assertThat(module.cleanCalled).isTrue();
+        assertThat(module.getContext()).isNull();
+
+        InOrder inOrder = inOrder(service1, service2);
+        inOrder.verify(service2).stop();
+        inOrder.verify(service1).stop();
+    }
+
+    @Test
+    public void start_should_log_exceptions_and_continue_when_service_fails_to_start()
+    {
+        Service service1 = mock(Service.class);
+        Service service2 = mock(Service.class);
+
+        RuntimeException exception = new RuntimeException("start failed");
+        doThrow(exception).when(service1).start();
+
+        module.addService(service1);
+        module.addService(service2);
+
+        module.start(context);
+
+        verify(service2).start();
+        verify(logger).error(startsWith("Could not start service"), eq(exception));
+    }
+
+    @Test
+    public void stop_should_log_exceptions_and_continue_when_service_fails_to_stop()
+    {
+        Service service1 = mock(Service.class);
+        Service service2 = mock(Service.class);
+
+        RuntimeException exception = new RuntimeException("stop failed");
+        doThrow(exception).when(service2).stop();
+
+        module.addService(service1);
+        module.addService(service2);
+
+        module.start(context);
+        module.stop();
+
+        verify(service1).stop();
+        verify(logger).error(startsWith("Could not stop service"), eq(exception));
+    }
+
+    @Test
+    public void constructor_should_replace_existing_instance_and_transfer_context_when_override_is_true()
+    {
+        Service service = mock(Service.class);
+        module.addService(service);
+        module.start(context);
+
+        TestModule newModule = new TestModule(true, logger);
+
+        assertThat(module.cleanCalled).isTrue();
+        verify(service).stop();
+
+        assertThat(newModule.getContext()).isEqualTo(context);
+        assertThat(newModule.prepareCalled).isTrue();
+
+        assertThat(TestModule.instance).isEqualTo(newModule);
+    }
+
+    @Test
+    public void constructor_should_not_replace_existing_instance_when_override_is_false()
+    {
+        TestModule newModule = new TestModule(false, logger);
+
+        assertThat(module.cleanCalled).isFalse();
+        assertThat(TestModule.instance).isEqualTo(module);
+    }
+
+    private static class TestModule extends Module<TestModule>
+    {
+        static TestModule instance;
+        boolean prepareCalled;
+        boolean cleanCalled;
+        private final Logger logger;
+
+        TestModule(boolean override, Logger logger)
+        {
+            super(override);
+            this.logger = logger;
+            if (override || instance == null) {
+                instance = this;
+            }
+        }
+
+        @Override
+        protected TestModule getInstance()
+        {
+            return instance;
+        }
+
+        @Override
+        protected void setInstance(TestModule inst)
+        {
+            if (inst != this) {
+                 instance = inst;
+            }
+        }
+
+        @Override
+        protected void prepare()
+        {
+            prepareCalled = true;
+        }
+
+        @Override
+        protected void clean()
+        {
+            cleanCalled = true;
+        }
+
+        @Override
+        public Logger getLogger()
+        {
+            return logger;
+        }
+
+        public void addService(Service s)
+        {
+            registerService(s);
+        }
+    }
+}
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