Add unit tests for running commands from custom context.

SwiftShellTests/Context_Tests.swift

@@ -9,7 +9,7 @@
 import XCTest
 import SwiftShell
 
-class Context_Tests: XCTestCase {
+class MainContext_Tests: XCTestCase {
 
 	func testCurrentDirectory_IsCurrentDirectory () {
 		XCTAssertEqual( main.currentdirectory, NSFileManager.defaultManager().currentDirectoryPath )
@@ -22,6 +22,9 @@ class Context_Tests: XCTestCase {
 		XCTAssertEqual( main.run("/bin/pwd"), "/tmp" )
 		XCTAssertEqual( main.currentdirectory, NSFileManager.defaultManager().currentDirectoryPath )
 	}
+}
+
+class ShellContext_Tests: XCTestCase {
 
 	func testBlankShellContext () {
 		let context = ShellContext()
@@ -34,4 +37,34 @@ class Context_Tests: XCTestCase {
 
 		XCTAssert( context.stdin === main.stdin )
 	}
+
+	func testRunCommand () {
+		let context = ShellContext()
+
+		XCTAssertEqual(context.run("echo", "one"), "one")
+	}
+
+	func testRunAsyncCommand () {
+		let context = ShellContext()
+		let task = context.runAsync("echo", "one")
+
+		XCTAssertEqual(task.stdout.read(), "one\n")
+	}
+
+	func testRunAndPrintCommand () {
+		var context = ShellContext()
+
+		AssertNoThrow {
+			try context.runAndPrint("echo", "one") // sent to null
+		}
+
+		let outputpipe = NSPipe()
+		context.stdout = outputpipe.fileHandleForWriting
+		let output = outputpipe.fileHandleForReading
+
+		AssertNoThrow {
+			try context.runAndPrint("echo", "two")
+		}
+		XCTAssertEqual(output.readSome(), "two\n")
+	}
 }