1 files changed, 72 insertions, 0 deletions
diff --git a/chapter01/src/test/java/com/seaofnodes/simple/ParserTest.java b/chapter01/src/test/java/com/seaofnodes/simple/ParserTest.java
new file mode 100644
index 00000000..887f63b8
--- /dev/null
+++ b/chapter01/src/test/java/com/seaofnodes/simple/ParserTest.java
@@ -0,0 +1,72 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.node.*;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class ParserTest {
+
+    @Test
+    public void testSimpleProgram() {
+        Parser parser = new Parser();
+        StartNode startNode = parser.parse("return 1;");
+        assertNotNull(startNode);
+        assertEquals(2, startNode.nOuts());
+        for (int i = 0; i < startNode.nOuts(); i++) {
+            switch( startNode.out(i) ) {
+            case ReturnNode ret:
+                assertEquals(2, ret.nIns());
+                assertEquals(startNode, ret.in(0));
+                assertTrue(ret.in(1) instanceof ConstantNode);
+                break;
+            case ConstantNode con:
+                assertEquals(1, con._value);
+                assertEquals(1, con.nIns());
+                assertEquals(startNode, con.in(0));
+                break;
+            default:
+                throw new IllegalStateException();
+            }
+        }
+    }
+
+    @Test
+    public void testZero() {
+        Parser parser = new Parser();
+        StartNode start = parser.parse("return 0;");
+        for( Node use : start._outputs )
+            if( use instanceof ConstantNode con )
+                assertEquals(0,con._value);
+    }
+
+    @Test
+    public void testBad1() {
+        try { new Parser().parse("ret"); }
+        catch( RuntimeException e ) { assertEquals("syntax error, expected return: ret",e.getMessage()); }
+    }
+
+    @Test
+    public void testBad2() {
+        try { new Parser().parse("return 0123;"); }
+        catch( RuntimeException e ) { assertEquals("syntax error: integer values cannot start with '0'",e.getMessage()); }
+    }
+
+    @Test
+    public void testBad3() {
+        try { new Parser().parse("return --12;"); }
+        catch( RuntimeException e ) { assertEquals("syntax error, expected integer literal: --",e.getMessage()); }
+    }
+
+    @Test
+    public void testBad4() {
+        try { new Parser().parse("return 100"); }
+        catch( RuntimeException e ) { assertTrue(e.getMessage().contains("syntax error, expected ; got :")); }
+    }
+
+    // Negative numbers require unary operator support that is not in scope
+    @Test
+    public void testBad5() {
+        try { new Parser().parse("return -100;"); }
+        catch( RuntimeException e ) { assertEquals("syntax error, expected integer literal: -", e.getMessage()); }
+    }
+}