Added tests, fixed brackets issue

src/main/java/printer/ExpressionPrinter.java

@@ -11,7 +11,7 @@ public class ExpressionPrinter extends Visitor<String> {
     }
 
     public String visitAddition(Addition addition) {
-        return "(" + visit(addition.leftHandSide) + " + " + visit(addition.rightHandSide) + ")";
+        return visit(addition.leftHandSide) + " + " + visit(addition.rightHandSide);
     }
 
     public String visitIdentifier(Identifier identifier) {
@@ -23,7 +23,7 @@ public class ExpressionPrinter extends Visitor<String> {
     }
 
     public String visitSubtraction(Subtraction subtraction) {
-        return "(" + visit(subtraction.leftHandSide) + " - " + visit(subtraction.rightHandSide) + ")";
+        return visit(subtraction.leftHandSide) + " - " + visit(subtraction.rightHandSide);
     }
 
     public String getValue() {

src/test/java/printer/ExpressionPrinterTest.java

@@ -0,0 +1,49 @@
+package printer;
+
+import expression.*;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+/**
+ * Created by nils on 15.01.2017.
+ */
+public class ExpressionPrinterTest {
+    final String identifierCode = "a";
+    final Identifier identifier = new Identifier(identifierCode);
+
+    final String integerCode = "42";
+    final Int integer = new Int(42);
+
+    final String additionCode = "a + 42";
+    final Addition addition = new Addition(new Identifier("a"), new Int(42));
+
+    final String subtractionCode = "1 - a";
+    final Subtraction subtraction = new Subtraction(new Int(1), new Identifier("a"));
+
+
+    @Test
+    public void testVisitAddition() {
+        ExpressionPrinter printer = new ExpressionPrinter(addition);
+        assertEquals(additionCode, printer.getValue());
+    }
+
+    @Test
+    public void testVisitIdentifier() {
+        ExpressionPrinter printer = new ExpressionPrinter(identifier);
+        assertEquals(identifierCode, printer.getValue());
+    }
+
+    @Test
+    public void testVisitInt() {
+        ExpressionPrinter printer = new ExpressionPrinter(integer);
+        assertEquals(integerCode, printer.getValue());
+    }
+
+    @Test
+    public void testVisitSubtraction() {
+        ExpressionPrinter printer = new ExpressionPrinter(subtraction);
+        assertEquals(subtractionCode, printer.getValue());
+    }
+
+}

src/test/java/printer/ProgramPrinterTest.java

@@ -0,0 +1,58 @@
+package printer;
+
+import expression.Addition;
+import expression.Identifier;
+import expression.Int;
+import expression.Subtraction;
+import org.junit.Test;
+import program.*;
+
+import static org.junit.Assert.*;
+
+public class ProgramPrinterTest {
+    final String loopCode = "while (a) { r := r + b ; a := a - 1 }";
+    final Loop loop = new Loop(new Identifier("a"), new Composition(new Assignment(new Identifier("r"), new Addition(new Identifier("r"), new Identifier("b"))), new Assignment(new Identifier("a"), new Subtraction(new Identifier("a"), new Int(1)))));
+
+    final String assignmentCode = "a := 2";
+    final Assignment assignment = new Assignment(new Identifier("a"), new Int(2));
+
+    final String compositionCode = assignmentCode + " ; b := bar";
+    final Composition composition = new Composition(assignment, new Assignment(new Identifier("b"), new Identifier("bar")));
+
+    final String conditionalCode = "if (foo - bar) then { x := 5 } else { x := x }";
+    final Conditional conditional = new Conditional(new Subtraction(new Identifier("foo"), new Identifier("bar")), new Assignment(new Identifier("x"), new Int(5)), new Assignment(new Identifier("x"), new Identifier("x")));
+
+    final String programCode = compositionCode + " ; " + loopCode + " ; " + conditionalCode;
+    final Program program = new Composition(new Composition(composition, loop), conditional);
+
+    @Test
+    public void testVisitAssignment() {
+        ProgramPrinter printer = new ProgramPrinter(assignment);
+        assertEquals(assignmentCode, printer.getValue());
+    }
+
+    @Test
+    public void testVisitComposition() {
+        ProgramPrinter printer = new ProgramPrinter(composition);
+        assertEquals(compositionCode, printer.getValue());
+    }
+
+    @Test
+    public void testVisitConditional() {
+        ProgramPrinter printer = new ProgramPrinter(conditional);
+        assertEquals(conditionalCode, printer.getValue());
+    }
+
+    @Test
+    public void testVisitLoop() {
+        ProgramPrinter printer = new ProgramPrinter(loop);
+        assertEquals(loopCode, printer.getValue());
+    }
+
+    @Test
+    public void testVisitProgram() {
+        ProgramPrinter printer = new ProgramPrinter(program);
+        assertEquals(programCode, printer.getValue());
+    }
+
+}