Fix ArgumentList with multiple values.

PainlessInjection/PainlessInjection/ArgumentList.swift

@@ -19,7 +19,7 @@ public struct ArgumentList {
             FatalErrorNotifier.currentNotifier.notify("Expected \(T.self) parameter at index \(index) but got nothing: file \(file), line \(line)")
             return nil
         }
-        if let value = _args[0] as? T {
+        if let value = _args[index] as? T {
             return value
         }
         FatalErrorNotifier.currentNotifier.notify("Expected \(T.self) parameter at index \(index) but got \(_args[0].dynamicType): file \(file), line \(line)")

PainlessInjection/PainlessInjectionTests/ArgumentListTests.swift

@@ -43,7 +43,18 @@ class ArgumentListTests: XCTestCase {
         let line = #line - 2
         
         notifier.assertLastMessage("Expected NSDictionary parameter at index 0 but got nothing: file \(file), line \(line)")
-
+    }
+    
+    func testShouldUseMultipleParams() {
+        let list = ArgumentList(args: ["Hello", 12])
+        
+        let text: String = list.at(0)
+        let number: Int = list.at(1)
+        
+        XCTAssertEqual(text, "Hello")
+        XCTAssertEqual(number, 12)
+        notifier.assertNotErrors()
+        
     }
     
 }

PainlessInjection/PainlessInjectionTests/Fixtures.swift

@@ -44,6 +44,10 @@ class TestFatalErrorNotifier: FatalErrorNotifierProtocol {
         lastMessage = message
     }
     
+    func assertNotErrors(file: StaticString = #file, line: UInt = #line) {
+        XCTAssertNil(lastMessage, "Should not raise any errors")
+    }
+    
     func assertLastMessage(message: String, file: StaticString = #file, line: UInt = #line) {
         XCTAssertEqual(lastMessage!, message, file: file, line: line)
     }