1 files changed, 21 insertions, 1 deletions
diff --git a/src/test/java/org/shedlang/compiler/parser/ParserIntLiteralTests.java b/src/test/java/org/shedlang/compiler/parser/ParserIntLiteralTests.java
index bc0dcad9..f4865e1c 100644
--- a/src/test/java/org/shedlang/compiler/parser/ParserIntLiteralTests.java
+++ b/src/test/java/org/shedlang/compiler/parser/ParserIntLiteralTests.java
@@ -2,13 +2,13 @@ package org.shedlang.compiler.parser;
 
 import org.junit.jupiter.api.Test;
 
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.shedlang.compiler.ast.untyped.UntypedNodeMatchers.isUntypedIntLiteralNode;
 import static org.shedlang.compiler.parser.ParserTesting.parseString;
 import static org.zwobble.precisely.AssertThat.assertThat;
 
 public class ParserIntLiteralTests {
     // TODO: forbid negative zero?
-    // TODO: forbid leading zeroes?
 
     @Test
     public void canParseZero() {
@@ -54,4 +54,24 @@ public class ParserIntLiteralTests {
 
         assertThat(node, isUntypedIntLiteralNode(-723));
     }
+
+    @Test
+    public void leadingZeroesOnPositiveNumberAreForbidden() {
+        var source = "01";
+
+        assertThrows(
+            IntLiteralCannotHaveLeadingZeroesError.class,
+            () -> parseString(source, Parser::parseTopLevelExpression)
+        );
+    }
+
+    @Test
+    public void leadingZeroesOnNegativeNumberAreForbidden() {
+        var source = "-01";
+
+        assertThrows(
+            IntLiteralCannotHaveLeadingZeroesError.class,
+            () -> parseString(source, Parser::parseTopLevelExpression)
+        );
+    }
 }