Introduce variable filters

StencilTests/FilterTests.swift

@@ -0,0 +1,23 @@
+import XCTest
+import Stencil
+
+
+class FilterTests: XCTestCase {
+  func testCapitalizeFilter() {
+    let template = Template(templateString: "{{ name|capitalize }}")
+    let result = try? template.render(Context(dictionary: ["name": "kyle"]))
+    XCTAssertEqual(result, "Kyle")
+  }
+
+  func testUppercaseFilter() {
+    let template = Template(templateString: "{{ name|uppercase }}")
+    let result = try? template.render(Context(dictionary: ["name": "kyle"]))
+    XCTAssertEqual(result, "KYLE")
+  }
+
+  func testLowercaseFilter() {
+    let template = Template(templateString: "{{ name|lowercase }}")
+    let result = try? template.render(Context(dictionary: ["name": "Kyle"]))
+    XCTAssertEqual(result, "kyle")
+  }
+}

StencilTests/ParserTests.swift

@@ -17,13 +17,14 @@ class TokenParserTests: XCTestCase {
 
   func testParsingVariableToken() {
     let parser = TokenParser(tokens: [
-      Token.Variable(value: "name")
-      ])
+      Token.Variable(value: "'name'")
+    ])
 
     assertSuccess(try parser.parse()) { nodes in
       let node = nodes.first as! VariableNode
       XCTAssertEqual(nodes.count, 1)
-      XCTAssertEqual(node.variable, Variable("name"))
+      let result = try? node.render(Context())
+      XCTAssertEqual(result, "name")
     }
   }