Add assert and precondition

Dependencies.xcworkspace/xcshareddata/swiftpm/Package.resolved

@@ -14,8 +14,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/apple/swift-argument-parser",
       "state" : {
-        "revision" : "fddd1c00396eed152c45a46bea9f47b98e59301d",
-        "version" : "1.2.0"
+        "revision" : "46989693916f56d1186bd59ac15124caef896560",
+        "version" : "1.3.1"
       }
     },
     {
@@ -32,25 +32,34 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/pointfreeco/swift-clocks",
       "state" : {
-        "revision" : "d1fd837326aa719bee979bdde1f53cd5797443eb",
-        "version" : "1.0.0"
+        "revision" : "a8421d68068d8f45fbceb418fbf22c5dad4afd33",
+        "version" : "1.0.2"
       }
     },
     {
       "identity" : "swift-concurrency-extras",
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/pointfreeco/swift-concurrency-extras",
       "state" : {
-        "revision" : "ea631ce892687f5432a833312292b80db238186a",
-        "version" : "1.0.0"
+        "revision" : "bb5059bde9022d69ac516803f4f227d8ac967f71",
+        "version" : "1.1.0"
       }
     },
     {
       "identity" : "swift-docc-plugin",
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/apple/swift-docc-plugin",
       "state" : {
-        "revision" : "3303b164430d9a7055ba484c8ead67a52f7b74f6",
+        "revision" : "26ac5758409154cc448d7ab82389c520fa8a8247",
+        "version" : "1.3.0"
+      }
+    },
+    {
+      "identity" : "swift-docc-symbolkit",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-docc-symbolkit",
+      "state" : {
+        "revision" : "b45d1f2ed151d057b54504d653e0da5552844e34",
         "version" : "1.0.0"
       }
     },
@@ -59,35 +68,35 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/pointfreeco/swift-macro-testing",
       "state" : {
-        "revision" : "35acd9468d40ae87e75991a18af6271e8124c261",
-        "version" : "0.2.1"
+        "revision" : "5c4a1b9d7c23cd5c08ea50677d8e89080365cb00",
+        "version" : "0.4.0"
       }
     },
     {
       "identity" : "swift-snapshot-testing",
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/pointfreeco/swift-snapshot-testing",
       "state" : {
-        "revision" : "bb0ea08db8e73324fe6c3727f755ca41a23ff2f4",
-        "version" : "1.14.2"
+        "revision" : "625ccca8570773dd84a34ee51a81aa2bc5a4f97a",
+        "version" : "1.16.0"
       }
     },
     {
       "identity" : "swift-syntax",
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/apple/swift-syntax",
       "state" : {
-        "revision" : "ffa3cd6fc2aa62adbedd31d3efaf7c0d86a9f029",
-        "version" : "509.0.1"
+        "revision" : "303e5c5c36d6a558407d364878df131c3546fad8",
+        "version" : "510.0.2"
       }
     },
     {
       "identity" : "xctest-dynamic-overlay",
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/pointfreeco/xctest-dynamic-overlay",
       "state" : {
-        "revision" : "b13b1d1a8e787a5ffc71ac19dcaf52183ab27ba2",
-        "version" : "1.1.1"
+        "revision" : "6f30bdba373bbd7fbfe241dddd732651f2fbd1e2",
+        "version" : "1.1.2"
       }
     }
   ],

Package.resolved

@@ -14,8 +14,8 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/apple/swift-argument-parser",
       "state" : {
-        "revision" : "c8ed701b513cf5177118a175d85fbbbcd707ab41",
-        "version" : "1.3.0"
+        "revision" : "46989693916f56d1186bd59ac15124caef896560",
+        "version" : "1.3.1"
       }
     },
     {
@@ -68,35 +68,35 @@
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/pointfreeco/swift-macro-testing",
       "state" : {
-        "revision" : "90e38eec4bf661ec0da1bbfd3ec507d0f0c05310",
-        "version" : "0.3.0"
+        "revision" : "5c4a1b9d7c23cd5c08ea50677d8e89080365cb00",
+        "version" : "0.4.0"
       }
     },
     {
       "identity" : "swift-snapshot-testing",
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/pointfreeco/swift-snapshot-testing",
       "state" : {
-        "revision" : "5b0c434778f2c1a4c9b5ebdb8682b28e84dd69bd",
-        "version" : "1.15.4"
+        "revision" : "625ccca8570773dd84a34ee51a81aa2bc5a4f97a",
+        "version" : "1.16.0"
       }
     },
     {
       "identity" : "swift-syntax",
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/apple/swift-syntax",
       "state" : {
-        "revision" : "08a2f0a9a30e0f705f79c9cfaca1f68b71bdc775",
-        "version" : "510.0.0"
+        "revision" : "303e5c5c36d6a558407d364878df131c3546fad8",
+        "version" : "510.0.2"
       }
     },
     {
       "identity" : "xctest-dynamic-overlay",
       "kind" : "remoteSourceControl",
       "location" : "https://github.com/pointfreeco/xctest-dynamic-overlay",
       "state" : {
-        "revision" : "b13b1d1a8e787a5ffc71ac19dcaf52183ab27ba2",
-        "version" : "1.1.1"
+        "revision" : "6f30bdba373bbd7fbfe241dddd732651f2fbd1e2",
+        "version" : "1.1.2"
       }
     }
   ],

Sources/Dependencies/DependencyValues/Assert.swift

@@ -0,0 +1,196 @@
+extension DependencyValues {
+  /// A dependency for handling assertions.
+  ///
+  /// Useful as a controllable and testable substitute for Swift's `assert` function that calls
+  /// `XCTFail` in tests instead of terminating the executable.
+  ///
+  /// ```swift
+  /// func operate(_ n: Int) {
+  ///   @Dependency(\.assert) var assert
+  ///   assert(n > 0, "Number must be greater than zero")
+  ///   // ...
+  /// }
+  /// ```
+  ///
+  /// Tests can assert against this precondition using `XCTExpectFailure`:
+  ///
+  /// ```swift
+  /// XCTExpectFailure {
+  ///   operate(n)
+  /// } issueMatcher: {
+  ///   $0.compactDescription = "Number must be greater than zero"
+  /// }
+  /// ```
+  public var assert: any AssertionEffect {
+    get { self[AssertKey.self] }
+    set { self[AssertKey.self] = newValue }
+  }
+
+  /// A dependency for failing an assertion.
+  ///
+  /// Equivalent to passing a `false` condition to ``DependencyValues/assert``.
+  public var assertionFailure: any AssertionFailureEffect {
+    AssertionFailure(base: self.assert)
+  }
+
+  /// A dependency for handling preconditions.
+  ///
+  /// Useful as a controllable and testable substitute for Swift's `precondition` function that
+  /// calls `XCTFail` in tests instead of terminating the executable.
+  ///
+  /// ```swift
+  /// func operate(_ n: Int) {
+  ///   @Dependency(\.precondition) var precondition
+  ///   precondition(n > 0, "Number must be greater than zero")
+  ///   // ...
+  /// }
+  /// ```
+  ///
+  /// Tests can assert against this precondition using `XCTExpectFailure`:
+  ///
+  /// ```swift
+  /// XCTExpectFailure {
+  ///   operate(n)
+  /// } issueMatcher: {
+  ///   $0.compactDescription = "Number must be greater than zero"
+  /// }
+  /// ```
+  public var precondition: any AssertionEffect {
+    get { self[PreconditionKey.self] }
+    set { self[PreconditionKey.self] = newValue }
+  }
+}
+
+/// A type for creating an assertion or precondition.
+///
+/// See ``DependencyValues/assert`` or ``DependencyValues/precondition`` for more information.
+public protocol AssertionEffect: Sendable {
+  func callAsFunction(
+    _ condition: @autoclosure () -> Bool,
+    _ message: @autoclosure () -> String,
+    file: StaticString,
+    line: UInt
+  )
+}
+
+extension AssertionEffect {
+  @_disfavoredOverload
+  @_transparent
+  public func callAsFunction(
+    _ condition: @autoclosure () -> Bool,
+    _ message: @autoclosure () -> String = "",
+    file: StaticString = #file,
+    line: UInt = #line
+  ) {
+    self.callAsFunction(condition(), message(), file: file, line: line)
+  }
+}
+
+private struct LiveAssertionEffect: AssertionEffect {
+  @_transparent
+  func callAsFunction(
+    _ condition: @autoclosure () -> Bool,
+    _ message: @autoclosure () -> String,
+    file: StaticString,
+    line: UInt
+  ) {
+    Swift.assert(condition(), message(), file: file, line: line)
+  }
+}
+
+private struct LivePreconditionEffect: AssertionEffect {
+  @_transparent
+  func callAsFunction(
+    _ condition: @autoclosure () -> Bool,
+    _ message: @autoclosure () -> String,
+    file: StaticString,
+    line: UInt
+  ) {
+    Swift.precondition(condition(), message(), file: file, line: line)
+  }
+}
+
+private struct TestAssertionEffect: AssertionEffect {
+  @_transparent
+  func callAsFunction(
+    _ condition: @autoclosure () -> Bool,
+    _ message: @autoclosure () -> String,
+    file: StaticString,
+    line: UInt
+  ) {
+    guard condition() else { return XCTFail(message(), file: file, line: line) }
+  }
+}
+
+public protocol AssertionFailureEffect: Sendable {
+  func callAsFunction(
+    _ message: @autoclosure () -> String,
+    file: StaticString,
+    line: UInt
+  )
+}
+
+extension AssertionFailureEffect {
+  @_disfavoredOverload
+  @_transparent
+  public func callAsFunction(
+    _ message: @autoclosure () -> String = "",
+    file: StaticString = #file,
+    line: UInt = #line
+  ) {
+    self.callAsFunction(message(), file: file, line: line)
+  }
+}
+
+private struct AssertionFailure: AssertionFailureEffect {
+  let base: any AssertionEffect
+
+  @_transparent
+  func callAsFunction(
+    _ message: @autoclosure () -> String,
+    file: StaticString,
+    line: UInt
+  ) {
+    self.base(false, message(), file: file, line: line)
+  }
+}
+
+private enum AssertKey: DependencyKey {
+  public static let liveValue: any AssertionEffect = LiveAssertionEffect()
+  public static let testValue: any AssertionEffect = TestAssertionEffect()
+}
+
+private enum PreconditionKey: DependencyKey {
+  public static let liveValue: any AssertionEffect = LivePreconditionEffect()
+  public static let testValue: any AssertionEffect = TestAssertionEffect()
+}
+
+/// An ``AssertionEffect`` that invokes the given closure.
+public struct AnyAssertionEffect: AssertionEffect {
+  private let assert: @Sendable (
+    _ condition: @autoclosure () -> Bool,
+    _ message: @autoclosure () -> String,
+    _ file: StaticString,
+    _ line: UInt
+  ) -> Void
+
+  public init(
+    _ assert: @escaping @Sendable (
+      _ condition: @autoclosure () -> Bool,
+      _ message: @autoclosure () -> String,
+      _ file: StaticString,
+      _ line: UInt
+    ) -> Void
+  ) {
+    self.assert = assert
+  }
+
+  public func callAsFunction(
+    _ condition: @autoclosure () -> Bool,
+    _ message: @autoclosure () -> String,
+    file: StaticString,
+    line: UInt
+  ) {
+    self.assert(condition(), message(), file, line)
+  }
+}

Sources/Dependencies/Documentation.docc/Extensions/DependencyValues.md

@@ -5,7 +5,7 @@
 ### Creating and accessing values
 
 - ``init()``
-- ``subscript(_:_:_:_:)``
+- ``subscript(key:file:function:line:)
 
 ### Overriding values
 
@@ -18,6 +18,8 @@
 
 ### Dependency values
 
+- ``assert``
+- ``assertionFailure``
 - ``calendar``
 - ``context``
 - ``continuousClock``
@@ -27,6 +29,7 @@
 - ``mainQueue``
 - ``mainRunLoop``
 - ``openURL``
+- ``precondition``
 - ``suspendingClock``
 - ``timeZone``
 - ``urlSession``

Sources/Dependencies/Documentation.docc/Extensions/DependencyValuesAssert.md

@@ -0,0 +1,12 @@
+# ``Dependencies/DependencyValues/assert``
+
+## Topics
+
+### Dependency values
+
+- ``AssertionEffect``
+- ``AssertionFailureEffect``
+
+### Custom assertions
+
+- ``AnyAssertionEffect``