Complete lexer implementation

StencilTests/LexerTests.swift

@@ -20,4 +20,30 @@ class LexerTests: XCTestCase {
         XCTAssertEqual(tokens.first!, Token.Text(value: "Hello World"))
     }
 
+    func testTokenizeComment() {
+        let lexer = Lexer(templateString:"{# Comment #}")
+        let tokens = lexer.tokenize()
+
+        XCTAssertEqual(tokens.count, 1)
+        XCTAssertEqual(tokens.first!, Token.Comment(value: "Comment"))
+    }
+
+    func testTokenizeVariable() {
+        let lexer = Lexer(templateString:"{{ Variable }}")
+        let tokens = lexer.tokenize()
+
+        XCTAssertEqual(tokens.count, 1)
+        XCTAssertEqual(tokens.first!, Token.Variable(value: "Variable"))
+    }
+
+    func testTokenizeMixture() {
+        let lexer = Lexer(templateString:"My name is {{ name }}.")
+        let tokens = lexer.tokenize()
+
+        XCTAssertEqual(tokens.count, 3)
+        XCTAssertEqual(tokens[0], Token.Text(value: "My name is "))
+        XCTAssertEqual(tokens[1], Token.Variable(value: "name"))
+        XCTAssertEqual(tokens[2], Token.Text(value: "."))
+    }
+
 }