Added unit tests

test/sexpression/SExpressionTester.java

@@ -2,10 +2,10 @@ package sexpression;
 
 import static org.junit.Assert.*;
 
-import org.junit.Before;
-import org.junit.Test;
+import org.junit.*;
 
 import error.ErrorManager;
+import function.UserDefinedFunction;
 import sexpression.LispNumber.InvalidNumberException;
 
 public class SExpressionTester {
@@ -78,6 +78,33 @@ public class SExpressionTester {
         assertSExpressionMatchesString(expected, list);
     }
 
+    @Test
+    public void testLambdaExpressionToString() {
+        String expected = "(LAMBDA)";
+        LambdaExpression lambda = new LambdaExpression(new Cons(new Symbol("lambda"), Nil.getUniqueInstance()), null);
+
+        assertSExpressionMatchesString(expected, lambda);
+    }
+
+    @Test
+    public void testLambdaExpressionGetLambdaExpression() {
+        String expected = "(LAMBDA)";
+        LambdaExpression lambda = new LambdaExpression(new Cons(new Symbol("lambda"), Nil.getUniqueInstance()), null);
+
+        assertSExpressionMatchesString(expected, lambda.getLambdaExpression());
+    }
+
+    @Test
+    public void testLambdaExpressionGetFunction() {
+        String expected = "(LAMBDA)";
+        UserDefinedFunction function = new UserDefinedFunction(expected, Nil.getUniqueInstance(),
+                                                               Nil.getUniqueInstance());
+        LambdaExpression lambda = new LambdaExpression(new Cons(new Symbol("lambda"), Nil.getUniqueInstance()),
+                                                       function);
+
+        assertEquals(function, lambda.getFunction());
+    }
+
     @Test
     public void testCarOfNilIsNil() {
         assertEquals(Nil.getUniqueInstance().getCar(), Nil.getUniqueInstance());

test/table/SymbolTableTester.java

@@ -0,0 +1,58 @@
+package table;
+
+import static org.junit.Assert.*;
+
+import org.junit.*;
+
+import sexpression.*;
+
+public class SymbolTableTester {
+
+    private SymbolTable symbolTable;
+
+    @Before
+    public void setUp() throws Exception {
+        symbolTable = new SymbolTable();
+    }
+
+    @Test
+    public void lookupSymbolNotInTable() {
+        assertFalse(symbolTable.contains("symbol"));
+    }
+
+    @Test
+    public void lookupSymbolInTable() {
+        symbolTable.put("symbol", Symbol.T);
+        assertTrue(symbolTable.contains("symbol"));
+    }
+
+    @Test
+    public void retrieveSymbolValue() {
+        symbolTable.put("symbol", Symbol.T);
+        assertEquals(symbolTable.get("symbol"), Symbol.T);
+    }
+
+    @Test
+    public void redefineSymbolValue() {
+        symbolTable.put("symbol", Symbol.T);
+        symbolTable.put("symbol", Nil.getUniqueInstance());
+        assertEquals(symbolTable.get("symbol"), Nil.getUniqueInstance());
+    }
+
+    @Test
+    public void checkParentTableIsCorrect() {
+        SymbolTable childTable = new SymbolTable(symbolTable);
+
+        assertEquals(childTable.getParent(), symbolTable);
+    }
+
+    @Test
+    public void lookupSymbolInParentTable() {
+        symbolTable.put("symbol", Symbol.T);
+        SymbolTable childTable = new SymbolTable(symbolTable);
+        SymbolTable parentTable = childTable.getParent();
+
+        assertEquals(parentTable.get("symbol"), Symbol.T);
+    }
+
+}