diff --git a/org.eclipse.example.calc/.classpath b/org.eclipse.example.calc/.classpath
index 18d70f0..b646dd2 100644
--- a/org.eclipse.example.calc/.classpath
+++ b/org.eclipse.example.calc/.classpath
@@ -1,6 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <classpath>
 	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="src" path="tst"/>
 	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.6"/>
+	<classpathentry kind="con" path="org.eclipse.pde.core.requiredPlugins"/>
 	<classpathentry kind="output" path="bin"/>
 </classpath>
diff --git a/org.eclipse.example.calc/.project b/org.eclipse.example.calc/.project
index 05f7dc5..3a1f808 100644
--- a/org.eclipse.example.calc/.project
+++ b/org.eclipse.example.calc/.project
@@ -10,8 +10,19 @@
 			<arguments>
 			</arguments>
 		</buildCommand>
+		<buildCommand>
+			<name>org.eclipse.pde.ManifestBuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+		<buildCommand>
+			<name>org.eclipse.pde.SchemaBuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
 	</buildSpec>
 	<natures>
 		<nature>org.eclipse.jdt.core.javanature</nature>
+		<nature>org.eclipse.pde.PluginNature</nature>
 	</natures>
 </projectDescription>
diff --git a/org.eclipse.example.calc/Calculator.launch b/org.eclipse.example.calc/Calculator.launch
index d3f8131..00bf1b2 100644
--- a/org.eclipse.example.calc/Calculator.launch
+++ b/org.eclipse.example.calc/Calculator.launch
@@ -7,6 +7,7 @@
 <listEntry value="1"/>
 </listAttribute>
 <mapAttribute key="org.eclipse.debug.core.preferred_launchers">
+<mapEntry key="[debug]" value="org.eclipse.jdt.launching.localJavaApplication"/>
 <mapEntry key="[run]" value="org.eclipse.jdt.launching.localJavaApplication"/>
 </mapAttribute>
 <stringAttribute key="org.eclipse.jdt.launching.MAIN_TYPE" value="org.eclipse.example.calc.internal.ui.Calculator"/>
diff --git a/org.eclipse.example.calc/META-INF/MANIFEST.MF b/org.eclipse.example.calc/META-INF/MANIFEST.MF
new file mode 100644
index 0000000..f371248
--- /dev/null
+++ b/org.eclipse.example.calc/META-INF/MANIFEST.MF
@@ -0,0 +1,12 @@
+Manifest-Version: 1.0
+Bundle-ManifestVersion: 2
+Bundle-Name: Calculator
+Bundle-SymbolicName: org.eclipse.example.calc
+Bundle-Version: 0.1.0.qualifier
+Bundle-ActivationPolicy: lazy
+Bundle-RequiredExecutionEnvironment: J2SE-1.6
+Require-Bundle: org.junit4;bundle-version="[4.3.0,5.0.0)",
+ org.hamcrest;bundle-version="[1.1.0,2.0.0)"
+Export-Package: org.eclipse.example.calc;version="0.1.0",
+ org.eclipse.example.calc.internal.operations;version="0.1.0";x-internal:=true,
+ org.eclipse.example.calc.internal.ui;version="0.1.0";x-internal:=true
diff --git a/org.eclipse.example.calc/build.properties b/org.eclipse.example.calc/build.properties
new file mode 100644
index 0000000..1c56dd0
--- /dev/null
+++ b/org.eclipse.example.calc/build.properties
@@ -0,0 +1,4 @@
+source.. = src/,\
+           tst/
+bin.includes = META-INF/,\
+               .
diff --git a/org.eclipse.example.calc/org.eclipse.example.calc--All-Tests.launch b/org.eclipse.example.calc/org.eclipse.example.calc--All-Tests.launch
new file mode 100644
index 0000000..0723143
--- /dev/null
+++ b/org.eclipse.example.calc/org.eclipse.example.calc--All-Tests.launch
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<launchConfiguration type="org.eclipse.jdt.junit.launchconfig">
+<stringAttribute key="bad_container_name" value="org.eclipse.example.calc--All-Tests"/>
+<listAttribute key="org.eclipse.debug.core.MAPPED_RESOURCE_PATHS">
+<listEntry value="/org.eclipse.example.calc/tst"/>
+</listAttribute>
+<listAttribute key="org.eclipse.debug.core.MAPPED_RESOURCE_TYPES">
+<listEntry value="2"/>
+</listAttribute>
+<stringAttribute key="org.eclipse.jdt.junit.CONTAINER" value="=org.eclipse.example.calc/tst"/>
+<booleanAttribute key="org.eclipse.jdt.junit.KEEPRUNNING_ATTR" value="false"/>
+<stringAttribute key="org.eclipse.jdt.junit.TESTNAME" value=""/>
+<stringAttribute key="org.eclipse.jdt.junit.TEST_KIND" value="org.eclipse.jdt.junit.loader.junit4"/>
+<stringAttribute key="org.eclipse.jdt.launching.MAIN_TYPE" value=""/>
+<stringAttribute key="org.eclipse.jdt.launching.PROJECT_ATTR" value="org.eclipse.example.calc"/>
+<stringAttribute key="org.eclipse.jdt.launching.VM_ARGUMENTS" value="-ea"/>
+</launchConfiguration>
diff --git a/org.eclipse.example.calc/tst/org/eclipse/example/calc/OperationsTest.java b/org.eclipse.example.calc/tst/org/eclipse/example/calc/OperationsTest.java
new file mode 100644
index 0000000..cbb081a
--- /dev/null
+++ b/org.eclipse.example.calc/tst/org/eclipse/example/calc/OperationsTest.java
@@ -0,0 +1,73 @@
+/*******************************************************************************
+ * Copyright (C) 2010, Matthias Sohn <matthias.sohn@sap.com>
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *******************************************************************************/
+package org.eclipse.example.calc;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+import org.eclipse.example.calc.internal.operations.Equals;
+import org.eclipse.example.calc.internal.operations.Minus;
+import org.eclipse.example.calc.internal.operations.Plus;
+import org.eclipse.example.calc.internal.operations.Square;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+public class OperationsTest {
+
+	private Square square;
+
+	@Before
+	public void setUp() throws Exception {
+		new Plus();
+		new Minus();
+		new Equals();
+		square = new Square();
+	}
+
+	@After
+	public void tearDown() throws Exception {
+		Operations.INSTANCE.reset();
+	}
+
+	@Test
+	public void testRegister() {
+		assertTrue(Operations.INSTANCE.getOperation(square.getName()) instanceof Square);
+		try {
+			new Square();
+			fail("double registration of same operation must fail");
+		} catch (AssertionError a) {
+			// expected
+		}
+	}
+
+	@Test
+	public void testGetOperation() {
+		assertTrue(Operations.INSTANCE.getOperation("+") instanceof Plus);
+		assertTrue(Operations.INSTANCE.getOperation("-") instanceof Minus);
+		assertTrue(Operations.INSTANCE.getOperation("=") instanceof Equals);
+		assertTrue(Operations.INSTANCE.getOperation("x²") instanceof Square);
+	}
+
+	@Test
+	public void testSize() {
+		assertEquals(4, Operations.INSTANCE.size());
+	}
+
+	@Test
+	public void testGetOperationName() {
+		for (int i = 0; i < Operations.INSTANCE.size(); i++) {
+			String name = Operations.INSTANCE.getOperationName(i);
+			Operation op = Operations.INSTANCE.getOperation(name);
+			assertEquals(name, op.getName());
+		}
+	}
+
+}
diff --git a/org.eclipse.example.calc/tst/org/eclipse/example/calc/internal/operations/AbstractOperationTest.java b/org.eclipse.example.calc/tst/org/eclipse/example/calc/internal/operations/AbstractOperationTest.java
new file mode 100644
index 0000000..60eaa66
--- /dev/null
+++ b/org.eclipse.example.calc/tst/org/eclipse/example/calc/internal/operations/AbstractOperationTest.java
@@ -0,0 +1,20 @@
+/*******************************************************************************
+ * Copyright (C) 2010, Matthias Sohn <matthias.sohn@sap.com>
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *******************************************************************************/
+package org.eclipse.example.calc.internal.operations;
+
+import org.eclipse.example.calc.Operations;
+import org.junit.After;
+
+public abstract class AbstractOperationTest {
+
+	@After
+	public void tearDown() throws Exception {
+		Operations.INSTANCE.reset();
+	}
+}
diff --git a/org.eclipse.example.calc/tst/org/eclipse/example/calc/internal/operations/EqualsTest.java b/org.eclipse.example.calc/tst/org/eclipse/example/calc/internal/operations/EqualsTest.java
new file mode 100644
index 0000000..9af36a2
--- /dev/null
+++ b/org.eclipse.example.calc/tst/org/eclipse/example/calc/internal/operations/EqualsTest.java
@@ -0,0 +1,31 @@
+/*******************************************************************************
+ * Copyright (C) 2010, Matthias Sohn <matthias.sohn@sap.com>
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *******************************************************************************/
+package org.eclipse.example.calc.internal.operations;
+
+import static org.junit.Assert.assertEquals;
+
+import org.eclipse.example.calc.Operation;
+import org.junit.Before;
+import org.junit.Test;
+
+public class EqualsTest extends AbstractOperationTest {
+
+	private Operation op;
+
+	@Before
+	public void setUp() throws Exception {
+		op = new Equals();
+	}
+
+	@Test
+	public void testGetName() {
+		assertEquals(op.getName(), "=");
+	}
+
+}
diff --git a/org.eclipse.example.calc/tst/org/eclipse/example/calc/internal/operations/MinusTest.java b/org.eclipse.example.calc/tst/org/eclipse/example/calc/internal/operations/MinusTest.java
new file mode 100644
index 0000000..9e5126f
--- /dev/null
+++ b/org.eclipse.example.calc/tst/org/eclipse/example/calc/internal/operations/MinusTest.java
@@ -0,0 +1,35 @@
+/*******************************************************************************
+ * Copyright (C) 2010, Matthias Sohn <matthias.sohn@sap.com>
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *******************************************************************************/
+package org.eclipse.example.calc.internal.operations;
+
+import static org.junit.Assert.assertEquals;
+
+import org.eclipse.example.calc.BinaryOperation;
+import org.junit.Before;
+import org.junit.Test;
+
+public class MinusTest extends AbstractOperationTest {
+
+	private BinaryOperation op;
+
+	@Before
+	public void setUp() throws Exception {
+		op = new Minus();
+	}
+
+	@Test
+	public void testPerform() {
+		assertEquals(-1.0, op.perform(1.0F, 2.0F), 0.01F);
+	}
+
+	@Test
+	public void testGetName() {
+		assertEquals(op.getName(), "-");
+	}
+}
diff --git a/org.eclipse.example.calc/tst/org/eclipse/example/calc/internal/operations/PlusTest.java b/org.eclipse.example.calc/tst/org/eclipse/example/calc/internal/operations/PlusTest.java
new file mode 100644
index 0000000..4f4cd74
--- /dev/null
+++ b/org.eclipse.example.calc/tst/org/eclipse/example/calc/internal/operations/PlusTest.java
@@ -0,0 +1,36 @@
+/*******************************************************************************
+ * Copyright (C) 2010, Matthias Sohn <matthias.sohn@sap.com>
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *******************************************************************************/
+package org.eclipse.example.calc.internal.operations;
+
+import static org.junit.Assert.*;
+
+import org.eclipse.example.calc.BinaryOperation;
+import org.junit.Before;
+import org.junit.Test;
+
+public class PlusTest extends AbstractOperationTest {
+
+	private BinaryOperation op;
+
+	@Before
+	public void setUp() throws Exception {
+		op = new Plus();
+	}
+
+	@Test
+	public void testPerform() {
+		assertEquals(3.0, op.perform(1.0F, 2.0F), 0.01F);
+	}
+
+	@Test
+	public void testGetName() {
+		assertEquals(op.getName(), "+");
+	}
+
+}
diff --git a/org.eclipse.example.calc/tst/org/eclipse/example/calc/internal/operations/SquareTest.java b/org.eclipse.example.calc/tst/org/eclipse/example/calc/internal/operations/SquareTest.java
new file mode 100644
index 0000000..5ae112f
--- /dev/null
+++ b/org.eclipse.example.calc/tst/org/eclipse/example/calc/internal/operations/SquareTest.java
@@ -0,0 +1,35 @@
+/*******************************************************************************
+ * Copyright (C) 2010, Matthias Sohn <matthias.sohn@sap.com>
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *******************************************************************************/
+package org.eclipse.example.calc.internal.operations;
+
+import static org.junit.Assert.assertEquals;
+
+import org.eclipse.example.calc.UnaryOperation;
+import org.junit.Before;
+import org.junit.Test;
+
+public class SquareTest extends AbstractOperationTest {
+
+	private UnaryOperation op;
+
+	@Before
+	public void setUp() throws Exception {
+		op = new Square();
+	}
+
+	@Test
+	public void testPerform() {
+		assertEquals(4.0, op.perform(2.0F), 0.01F);
+	}
+
+	@Test
+	public void testGetName() {
+		assertEquals(op.getName(), "x²");
+	}
+}