Started writing tests for the builtin functions

src/function/builtin/APPLY.java

@@ -3,65 +3,46 @@ package function.builtin;
 import function.*;
 import sexpression.*;
 
-/**
- * <code>APPLY</code> represents the APPLY function in Lisp.
- */
 public class APPLY extends LispFunction {
 
-    /**
-     * Call APPLY with the specified argument list.
-     *
-     * @param argList
-     *            the list of arguments to be sent to APPLY (MUST BE A PROPER LIST)
-     * @return the result of evaluating APPLY on <code>argList</code>
-     */
+    private static final int NUMBER_OF_ARGUMENTS = 2;
+    private ArgumentValidator argumentValidator;
+
     public static SExpression apply(Cons argList) {
         return new APPLY().call(argList);
     }
 
-    // The number of arguments that APPLY takes.
-    private static final int NUM_ARGS = 2;
+    public APPLY() {
+        this.argumentValidator = new ArgumentValidator("APPLY");
+        this.argumentValidator.setExactNumberOfArguments(NUMBER_OF_ARGUMENTS);
+    }
 
     public SExpression call(Cons argList) {
-        // retrieve the number of arguments passed to APPLY
-        int argListLength = LENGTH.getLength(argList);
+        argumentValidator.validate(argList);
 
-        // make sure we have received the proper number of arguments
-        if (argListLength != NUM_ARGS) {
-            Cons originalSExpr = new Cons(new Symbol("APPLY"), argList);
-            String errMsg = "too " + ((argListLength > NUM_ARGS) ? "many" : "few") + " arguments given to APPLY: "
-                            + originalSExpr;
-
-            throw new RuntimeException(errMsg);
-        }
-
-        SExpression car = argList.getCar(); // function name
         Cons cdr = (Cons) argList.getCdr();
-        SExpression cadr = cdr.getCar(); // argument list
+        SExpression functionName = argList.getCar();
+        SExpression argumentList = cdr.getCar();
 
-        // make sure the second argument is a list
-        if (cadr.listp()) {
-            LispFunction function = EVAL.lookupFunction(car.toString());
+        if (argumentList.listp()) {
+            LispFunction function = EVAL.lookupFunction(functionName.toString());
 
             if (function == null) {
-                // check if the car of the list is a lambda expression
-                if (car.functionp()) {
-                    function = ((LambdaExpression) car).getFunction();
-                } else if (LAMBDA.isLambdaExpression(car)) {
-                    Cons lexpr = (Cons) car;
+                if (functionName.functionp()) {
+                    function = ((LambdaExpression) functionName).getFunction();
+                } else if (LAMBDA.isLambdaExpression(functionName)) {
+                    Cons lexpr = (Cons) functionName;
 
                     function = LAMBDA.createFunction(lexpr);
                 } else {
-                    throw new RuntimeException("undefined function " + car);
+                    throw new RuntimeException("undefined function " + functionName);
                 }
             }
 
-            // apply the given function to the given argument list
-            return function.call((Cons) cadr);
+            return function.call((Cons) argumentList);
         }
 
-        // the second argument is not a list
-        throw new RuntimeException("APPLY: " + cadr + " is not a list");
+        throw new RuntimeException("APPLY: " + argumentList + " is not a list");
     }
 
 }

src/function/builtin/ATOM.java

@@ -1,32 +1,23 @@
 package function.builtin;
 
-import function.LispFunction;
+import function.*;
 import sexpression.*;
 
-/**
- * <code>ATOM</code> represents the ATOM function in Lisp.
- */
 public class ATOM extends LispFunction {
 
-    // The number of arguments that ATOM takes.
-    private static final int NUM_ARGS = 1;
+    private static final int NUMBER_OF_ARGUMENTS = 1;
+    private ArgumentValidator argumentValidator;
 
-    public SExpression call(Cons argList) {
-        // retrieve the number of arguments passed to ATOM
-        int argListLength = LENGTH.getLength(argList);
+    public ATOM() {
+        this.argumentValidator = new ArgumentValidator("ATOM");
+        this.argumentValidator.setExactNumberOfArguments(NUMBER_OF_ARGUMENTS);
+    }
 
-        // make sure we have received the proper number of arguments
-        if (argListLength != NUM_ARGS) {
-            Cons originalSExpr = new Cons(new Symbol("ATOM"), argList);
-            String errMsg = "too " + ((argListLength > NUM_ARGS) ? "many" : "few") + " arguments given to ATOM: "
-                            + originalSExpr;
+    public SExpression call(Cons argumentList) {
+        argumentValidator.validate(argumentList);
+        SExpression argument = argumentList.getCar();
 
-            throw new RuntimeException(errMsg);
-        }
-
-        SExpression arg = argList.getCar();
-
-        return (arg.atomp() ? Symbol.T : Nil.getUniqueInstance());
+        return argument.atomp() ? Symbol.T : Nil.getUniqueInstance();
     }
 
 }

test/function/UserDefinedFunctionTester.java

@@ -1,6 +1,7 @@
 package function;
 
 import static org.junit.Assert.assertEquals;
+import static testutil.TestUtilities.*;
 
 import org.junit.Test;
 
@@ -35,7 +36,7 @@ public class UserDefinedFunctionTester {
                                  new Cons(Nil.getUniqueInstance(),
                                           new Cons(Nil.getUniqueInstance(), Nil.getUniqueInstance())));
 
-        assertEquals(expected.toString(), function.getLambdaExpression().toString());
+        assertSExpressionsMatch(expected, function.getLambdaExpression());
     }
 
     @Test
@@ -44,7 +45,7 @@ public class UserDefinedFunctionTester {
         SExpression argument = new LispNumber(23);
         Cons argumentList = new Cons(argument, Nil.getUniqueInstance());
 
-        assertEquals(argument.toString(), function.call(argumentList).toString());
+        assertSExpressionsMatch(argument, function.call(argumentList));
     }
 
     @Test(expected = TooManyArgumentsException.class)

test/function/builtin/APPLYTester.java

@@ -0,0 +1,61 @@
+package function.builtin;
+
+import static testutil.TestUtilities.*;
+
+import org.junit.Test;
+
+import function.ArgumentValidator.*;
+import sexpression.Cons;
+
+public class APPLYTester {
+
+    @Test
+    public void testApply() {
+        String input = "(apply '+ '(1 2 3))";
+
+        assertSExpressionsMatch(evaluateString(input), parseString("6"));
+    }
+
+    @Test
+    public void testApplyWithLambdaExpression() {
+        String input = "(apply (lambda (x) (+ x 1)) '(25))";
+
+        assertSExpressionsMatch(evaluateString(input), parseString("26"));
+    }
+
+    @Test
+    public void testApplyWithQuotedLambdaExpression() {
+        String input = "(apply '(lambda (x) (+ x 1)) '(25))";
+
+        assertSExpressionsMatch(evaluateString(input), parseString("26"));
+    }
+
+    @Test
+    public void testStaticApplyCall() {
+        String argumentList = "(+ (25 10))";
+        Cons parsedArgumentList = (Cons) parseString(argumentList);
+
+        assertSExpressionsMatch(APPLY.apply(parsedArgumentList), parseString("35"));
+    }
+
+    @Test(expected = RuntimeException.class)
+    public void testApplyWithUndefinedFunction() {
+        evaluateString("(apply 'f '(1 2 3))");
+    }
+
+    @Test(expected = RuntimeException.class)
+    public void testApplyWithNonListSecondArgument() {
+        evaluateString("(apply '+ '2)");
+    }
+
+    @Test(expected = TooManyArgumentsException.class)
+    public void testApplyWithTooManyArguments() {
+        evaluateString("(apply '1 '2 '3)");
+    }
+
+    @Test(expected = TooFewArgumentsException.class)
+    public void testApplyWithTooFewArguments() {
+        evaluateString("(apply '1)");
+    }
+
+}

test/function/builtin/ATOMTester.java

@@ -0,0 +1,35 @@
+package function.builtin;
+
+import static testutil.TestUtilities.*;
+
+import org.junit.Test;
+
+import function.ArgumentValidator.*;
+
+public class ATOMTester {
+
+    @Test
+    public void testAtom_ReturnsTrue() {
+        String input = "(atom 'a)";
+
+        assertSExpressionsMatch(evaluateString(input), parseString("T"));
+    }
+
+    @Test
+    public void testAtom_ReturnsFalse() {
+        String input = "(atom '(1 2 3))";
+
+        assertSExpressionsMatch(evaluateString(input), parseString("()"));
+    }
+
+    @Test(expected = TooManyArgumentsException.class)
+    public void testApplyWithTooManyArguments() {
+        evaluateString("(atom '1 '2)");
+    }
+
+    @Test(expected = TooFewArgumentsException.class)
+    public void testApplyWithTooFewArguments() {
+        evaluateString("(atom)");
+    }
+
+}

test/parser/LispParserTester.java

@@ -1,7 +1,7 @@
 package parser;
 
 import static org.junit.Assert.*;
-import static parser.SExpressionTypeAssertions.*;
+import static testutil.SExpressionTypeAssertions.*;
 import static testutil.TestUtilities.createIOExceptionThrowingInputStream;
 import static testutil.TestUtilities.createInputStreamFromString;
 

test/testutil/SExpressionTypeAssertions.java

@@ -1,9 +1,8 @@
-package parser;
+package testutil;
 
 import static org.junit.Assert.*;
 
-import sexpression.Nil;
-import sexpression.SExpression;
+import sexpression.*;
 
 public final class SExpressionTypeAssertions {
 

test/testutil/TestUtilities.java

@@ -1,13 +1,19 @@
 package testutil;
 
+import static org.junit.Assert.assertEquals;
+
 import java.io.*;
 
+import function.builtin.EVAL;
+import parser.LispParser;
+import sexpression.SExpression;
+
 public final class TestUtilities {
 
     public static InputStream createInputStreamFromString(String string) {
         return new ByteArrayInputStream(string.getBytes());
     }
-    
+
     public static InputStream createIOExceptionThrowingInputStream() {
         return new InputStream() {
 
@@ -17,4 +23,18 @@ public final class TestUtilities {
         };
     }
 
+    public static SExpression evaluateString(String input) {
+        return EVAL.eval(parseString(input));
+    }
+
+    public static SExpression parseString(String input) {
+        InputStream stringInputStream = TestUtilities.createInputStreamFromString(input);
+
+        return new LispParser(stringInputStream, "testFile").getNextSExpression();
+    }
+
+    public static void assertSExpressionsMatch(SExpression one, SExpression two) {
+        assertEquals(one.toString(), two.toString());
+    }
+
 }