Add very minimal support for a scripting dictionary — only the getURL

AppleEvent — and add an XCTestCase that can run and verify results of
AppleScripts that target Evergreen.

EvergreenTests/ScriptingTests/ScriptingTests.swift

@@ -0,0 +1,81 @@
+//
+//  ScriptingTests.swift
+//  EvergreenTests
+//
+//  Created by Olof Hellman on 1/7/18.
+//  Copyright © 2018 Olof Hellman. All rights reserved.
+//
+
+import XCTest
+
+class ScriptingTests: XCTestCase {
+
+    override func setUp() {
+        super.setUp()
+    }
+    
+    override func tearDown() {
+        super.tearDown()
+    }
+
+    /*
+        @function doIndividualScript
+        @param filename -- name of a .applescript (sans extention) in the test bundle's 
+                           Resources/TestScripts directory
+        @brief  given a file, loads the script and runs it.  Expects a result from running
+                the script of the form
+                     {test_result:true, script_result:<anything>}
+                if the test_result is false or is missing, the test fails
+        @return  the value of script_result, if any
+    */
+    func doIndividualScript(filename:String) -> NSAppleEventDescriptor? {
+        var errorDict: NSDictionary? = nil
+        let testBundle = Bundle(for: type(of: self))
+        let url = testBundle.url(forResource:filename, withExtension:"applescript", subdirectory:"TestScripts")
+        guard let testScriptUrl = url  else {
+            XCTFail("Failed Getting script URL")
+            return nil
+        }
+        
+        guard let testScript = NSAppleScript(contentsOf: testScriptUrl, error: &errorDict) else {
+            XCTFail("Failed initializing NSAppleScript")
+            print ("error is \(String(describing: errorDict))")
+            return nil
+        }
+        
+        let scriptResult = testScript.executeAndReturnError(&errorDict)
+        if (errorDict != nil) {
+            XCTFail("Failed executing script")
+            print ("error is \(String(describing: errorDict))")
+            return nil
+        }
+        
+        let usrfDictionary = scriptResult.usrfDictionary()
+        guard let testResult = usrfDictionary["test_result"] else {
+            XCTFail("test script didn't return test result in usrf")
+            return nil
+        }
+        
+        XCTAssert(testResult.booleanValue == true, "test_result should be true")
+        
+        return usrfDictionary["script_result"]
+    }
+    
+    /*
+        @function testGenericScript
+        @brief  An example of how a script can be run as part of an XCTest
+                the applescript returns 
+                     {test_result:true, script_result:"Geoducks!"}
+                doIndividualScript() verifies the test_result portion
+                this code verifies the script_result portion
+    */
+    func testGenericScript() {
+        let scriptResult = doIndividualScript(filename: "testGenericScript")
+        XCTAssert( scriptResult?.stringValue == "Geoducks!")
+    }
+    
+    func testGetUrlScript() {
+        _ = doIndividualScript(filename: "testGetURL")
+    }
+
+}