         assertStringToTokens("# this is only a comment\n", [])
     }
     
-    
-    func testNumbers() {
+    func testTopLevelNumbers() {
         assertStringToExpression("0;", .Number(0))
         assertStringToExpression("00.00;", .Number(0))
         assertStringToExpression("10.0;", .Number(10))

import XCTest
@testable import KaleidoscopeLang

class KaleidoscopeLangTests: XCTestCase {
    func testIdentifierTokenizer() {
        assertMatched(identifierToken, "a".characters)
        assertMatched(identifierToken, "some".characters)
        assertMatched(identifierToken, "_some".characters)

        assertUnmatched(identifierToken, "2name".characters)
        assertUnmatched(identifierToken, "2".characters)
    }
    
    func testSimpleExpressions() {
        assertStringToTokens("a+b", [.Identifier("a"), .Character("+"), .Identifier("b")])
        
        assertStringToTokens(
            "def add(a b) a + b",
            [
