Add XCTUnwrap(_:case:) test helper. (#95)

* Add XCTUnwrap(_:case:) test helper.

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* Update Package.swift

* Update XCTUnwrap.swift

* Update XCTUnwrapTests.swift

* skip

* Update .github/workflows/ci.yml

* wip

* Update XCTUnwrap.swift

* Update Sources/CasePaths/XCTUnwrap.swift

Co-authored-by: Stephen Celis <[email protected]>

Author: mbrandonw

.github/workflows/ci.yml

@@ -13,32 +13,13 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
-  macos-11:
-    name: MacOS 11
-    runs-on: macos-11
+  macos-12:
+    name: MacOS 12
+    runs-on: macos-12
     strategy:
       matrix:
         xcode:
-          - 12.5.1
-          - '13.0'
-    steps:
-      - uses: actions/checkout@v2
-      - name: Select Xcode ${{ matrix.xcode }}
-        run: sudo xcode-select -s /Applications/Xcode_${{ matrix.xcode }}.app
-      - name: Print Swift version
-        run: swift --version
-      - name: Run tests
-        run: make test-swift
-
-  macos-10-15:
-    name: MacOS 10.15
-    runs-on: macos-10.15
-    strategy:
-      matrix:
-        xcode:
-          - 11.3
-          - 11.7
-          - 12.4
+          - '14.2'
     steps:
       - uses: actions/checkout@v2
       - name: Select Xcode ${{ matrix.xcode }}

Makefile

@@ -5,16 +5,14 @@ test-linux:
 		--rm \
 		-v "$(PWD):$(PWD)" \
 		-w "$(PWD)" \
-		swift:5.3 \
+		swift:5.5 \
 		bash -c 'make test-swift'
 
 test-swift:
 	swift test \
- 		--enable-test-discovery \
 		--parallel
 	swift test \
 		-c release \
- 		--enable-test-discovery \
 		--parallel
 
 format:

Package.resolved

@@ -1,27 +1,37 @@
-// swift-tools-version:5.2
+// swift-tools-version:5.5
 
 import PackageDescription
 
 let package = Package(
   name: "swift-case-paths",
+  platforms: [
+    .iOS(.v13),
+    .macOS(.v10_15),
+    .tvOS(.v13),
+    .watchOS(.v6),
+  ],
   products: [
     .library(
       name: "CasePaths",
       targets: ["CasePaths"]
     )
   ],
   dependencies: [
-    .package(name: "Benchmark", url: "https://github.com/google/swift-benchmark", from: "0.1.0")
+    .package(name: "Benchmark", url: "https://github.com/google/swift-benchmark", from: "0.1.0"),
+    .package(url: "https://github.com/pointfreeco/xctest-dynamic-overlay", from: "0.8.0"),
   ],
   targets: [
     .target(
-      name: "CasePaths"
+      name: "CasePaths",
+      dependencies: [
+        .product(name: "XCTestDynamicOverlay", package: "xctest-dynamic-overlay"),
+      ]
     ),
     .testTarget(
       name: "CasePathsTests",
       dependencies: ["CasePaths"]
     ),
-    .target(
+    .executableTarget(
       name: "swift-case-paths-benchmark",
       dependencies: [
         "CasePaths",

Package.swift

@@ -0,0 +1,38 @@
+import Foundation
+@_spi(CurrentTestCase) import XCTestDynamicOverlay
+
+/// Asserts that an enum value matches a particular case and returns the associated value.
+///
+/// - Parameters:
+///   - expression: An enum value.
+///   - extract: A closure that attempts to extract a particular case from the enum. You can supply
+///     a case path literal here, like '/Enum.case'.
+///   - message: An optional description of a failure.
+/// - Returns: The unwrapped associated value from the matched case of the enum.
+public func XCTUnwrap<Root, Case>(
+  _ expression: @autoclosure () throws -> Root,
+  case extract: (Root) -> Case?,
+  _ message: @autoclosure () -> String = "",
+  file: StaticString = #file,
+  line: UInt = #line
+) throws -> Case {
+  guard let value = try extract(expression())
+  else {
+    #if canImport(ObjectiveC)
+      _ = XCTCurrentTestCase?.perform(Selector(("setContinueAfterFailure:")), with: false)
+    #endif
+    let message = message()
+    XCTFail(
+      """
+      XCTUnwrap failed: expected non-nil value of type "\(Case.self)"\
+      \(message.isEmpty ? "" : " - " + message)
+      """,
+      file: file,
+      line: line
+    )
+    throw UnwrappingCase()
+  }
+  return value
+}
+
+private struct UnwrappingCase: Error {}

Sources/CasePaths/XCTUnwrap.swift

@@ -0,0 +1,37 @@
+#if DEBUG && (os(iOS) || os(macOS) || os(tvOS) || os(watchOS))
+  import CasePaths
+  import XCTest
+
+  final class XCTUnwrapTests: XCTestCase {
+    func testXCTUnwrapFailure() throws {
+      try XCTSkipIf(ProcessInfo.processInfo.environment["CI"] != nil)
+
+      XCTExpectFailure {
+        $0.compactDescription == """
+          XCTUnwrap failed: expected non-nil value of type "Error"
+          """
+      }
+      _ = try XCTUnwrap(Result<Int, Error>.success(2), case: /Result.failure)
+    }
+
+    func testXCTUnwrapFailure_WithMessage() throws {
+      try XCTSkipIf(ProcessInfo.processInfo.environment["CI"] != nil)
+
+      XCTExpectFailure {
+        $0.compactDescription == """
+          XCTUnwrap failed: expected non-nil value of type "Error" - Should be success
+          """
+      }
+      _ = try XCTUnwrap(Result<Int, Error>.success(2), case: /Result.failure, "Should be success")
+    }
+
+    func testXCTUnwrapPass() throws {
+      try XCTSkipIf(ProcessInfo.processInfo.environment["CI"] != nil)
+
+      XCTAssertEqual(
+        try XCTUnwrap(Result<Int, Error>.success(2), case: /Result.success),
+        2
+      )
+    }
+  }
+#endif