feat: Report describe/it inside XCTestCases using XCTest (#32)

Closes #2

CHANGELOG.md

@@ -2,6 +2,16 @@
 
 ## Master
 
+### Breaking
+
+- Using Spectre in Xcode has be re-hauled, there are now `describe` and `it`
+  methods on `XCTestCase` which can be used. When used, these tests will be ran
+  directly and reported as XCTest failures and therefore shown in Xcode and
+  Xcode sidebar as XCTest failures.
+
+  Use of the global test context, i.e, global `describe` and `it` is no longer
+  permitted when using Spectre with XCTest.
+
 ### Enhancements
 
 - Unhandled errors will now be reported from the invoked cases source map.

Sources/Spectre/Global.swift

@@ -6,15 +6,20 @@ import Darwin
 
 
 let globalContext: GlobalContext = {
+#if os(macOS)
+  if getenv("XCTestConfigurationFilePath") != nil {
+    fatalError("Use of global context is not permitted when running inside XCTest")
+  }
+#endif
   atexit { run() }
   return GlobalContext()
 }()
 
-public func describe(_ name: String, closure: (ContextType) -> Void) {
+public func describe(_ name: String, _ closure: (ContextType) -> Void) {
   globalContext.describe(name, closure: closure)
 }
 
-public func it(_ name: String, closure: @escaping () throws -> Void) {
+public func it(_ name: String, _ closure: @escaping () throws -> Void) {
   globalContext.it(name, closure: closure)
 }
 

Sources/Spectre/XCTest.swift

@@ -0,0 +1,38 @@
+#if os(macOS)
+import XCTest
+
+
+extension XCTestCase {
+  public func describe(_ name: String, _ closure: (ContextType) -> Void) {
+    let context = Context(name: name)
+    closure(context)
+    context.run(reporter: XcodeReporter(testCase: self))
+  }
+
+  public func it(_ name: String, closure: @escaping () throws -> Void) {
+    let `case` = Case(name: name, closure: closure)
+    `case`.run(reporter: XcodeReporter(testCase: self))
+  }
+}
+
+
+class XcodeReporter: ContextReporter {
+  let testCase: XCTestCase
+
+  init(testCase: XCTestCase) {
+    self.testCase = testCase
+  }
+
+  func report(_ name: String, closure: (ContextReporter) -> Void) {
+    closure(self)
+  }
+
+  func addSuccess(_ name: String)  {}
+
+  func addDisabled(_ name: String) {}
+
+  func addFailure(_ name: String, failure: FailureType) {
+    testCase.recordFailure(withDescription: "\(name): \(failure.reason)", inFile: failure.file, atLine: failure.line, expected: false)
+  }
+}
+#endif

Tests/LinuxMain.swift

@@ -1,4 +1,5 @@
+import Spectre
 import SpectreTests
 
-testExpectation()
-testFailure()
+describe("Expectation", testExpectation)
+describe("Failure", testFailure)

Tests/SpectreTests/ExpectationSpec.swift

@@ -1,8 +1,6 @@
 import Spectre
 
-
-public func testExpectation() {
-  describe("Expectation") {
+public let testExpectation: ((ContextType) -> Void) = {
   $0.it("can be created from a value") {
     let expectation = expect("value")
     let value = try expectation.expression()
@@ -192,4 +190,3 @@ public func testExpectation() {
     }
   }
 }
-}

Tests/SpectreTests/FailureSpec.swift

@@ -1,20 +1,19 @@
 import Spectre
 
-public func testFailure() {
-  describe("Failure") {
-    $0.it("throws an error") {
-      var didFail = false
+public let testFailure: ((ContextType) -> Void) = {
+  $0.it("throws an error") {
 
-      do {
-        throw failure("it's broken")
-      } catch {
-        didFail = true
-      }
+    var didFail = false
 
-      if !didFail {
-        // We cannot trust fail inside fails tests.
-        fatalError("Test failed")
-      }
+    do {
+      throw failure("it's broken")
+    } catch {
+      didFail = true
+    }
+
+    if !didFail {
+      // We cannot trust fail inside fails tests.
+      fatalError("Test failed")
     }
   }
 }

Tests/SpectreTests/XCTest.swift

@@ -1,8 +1,9 @@
 import XCTest
+import Spectre
 
 class SpectreTests: XCTestCase {
   func testSpectre() {
-    testFailure()
-    testExpectation()
+    describe("Failure", testFailure)
+    describe("Expectation", testExpectation)
   }
 }