Rename the failable map overload to compactMap (#1180)

And also provide another overload of map that takes in an optional and behaves much more closely to what the original map matcher does

Author: younata

Sources/Nimble/Matchers/Map.swift

@@ -29,9 +29,37 @@ public func map<T, U>(_ transform: @escaping (T) async throws -> U, _ matcher: s
 /// `map` works by transforming the expression to a value that the given matcher uses.
 ///
 /// For example, you might only care that a particular property on a method equals some other value.
+/// So, you could write `expect(myObject).to(map(\.someOptionalIntValue, equal(3))`.
+/// This is also useful in conjunction with ``satisfyAllOf`` to do a partial equality of an object.
+public func map<T, U>(_ transform: @escaping (T) throws -> U?, _ matcher: Matcher<U>) -> Matcher<T> {
+    Matcher { (received: Expression<T>) in
+        try matcher.satisfies(received.cast { value in
+            guard let value else { return nil }
+            return try transform(value)
+        })
+    }
+}
+
+/// `map` works by transforming the expression to a value that the given matcher uses.
+///
+/// For example, you might only care that a particular property on a method equals some other value.
+/// So, you could write `expect(myObject).to(map(\.someOptionalIntValue, equal(3))`.
+/// This is also useful in conjunction with ``satisfyAllOf`` to do a partial equality of an object.
+public func map<T, U>(_ transform: @escaping (T) async throws -> U?, _ matcher: some AsyncableMatcher<U>) -> AsyncMatcher<T> {
+    AsyncMatcher { (received: AsyncExpression<T>) in
+        try await matcher.satisfies(received.cast { value in
+            guard let value else { return nil }
+            return try await transform(value)
+        })
+    }
+}
+
+/// `compactMap` works by transforming the expression to a value that the given matcher uses.
+///
+/// For example, you might only care that a particular property on a method equals some other value.
 /// So, you could write `expect(myObject).to(compactMap({ $0 as? Int }, equal(3))`.
 /// This is also useful in conjunction with ``satisfyAllOf`` to match against a converted type.
-public func map<T, U>(_ transform: @escaping (T) throws -> U?, _ matcher: Matcher<U>) -> Matcher<T> {
+public func compactMap<T, U>(_ transform: @escaping (T) throws -> U?, _ matcher: Matcher<U>) -> Matcher<T> {
     Matcher { (received: Expression<T>) in
         let message = ExpectationMessage.expectedTo("Map from \(T.self) to \(U.self)")
 
@@ -47,12 +75,12 @@ public func map<T, U>(_ transform: @escaping (T) throws -> U?, _ matcher: Matche
     }
 }
 
-/// `map` works by transforming the expression to a value that the given matcher uses.
+/// `compactMap` works by transforming the expression to a value that the given matcher uses.
 ///
 /// For example, you might only care that a particular property on a method equals some other value.
 /// So, you could write `expect(myObject).to(compactMap({ $0 as? Int }, equal(3))`.
 /// This is also useful in conjunction with ``satisfyAllOf`` to match against a converted type.
-public func map<T, U>(_ transform: @escaping (T) async throws -> U?, _ matcher: some AsyncableMatcher<U>) -> AsyncMatcher<T> {
+public func compactMap<T, U>(_ transform: @escaping (T) async throws -> U?, _ matcher: some AsyncableMatcher<U>) -> AsyncMatcher<T> {
     AsyncMatcher { (received: AsyncExpression<T>) in
         let message = ExpectationMessage.expectedTo("Map from \(T.self) to \(U.self)")
 

Tests/NimbleTests/Matchers/MapTest.swift

@@ -158,4 +158,91 @@ final class MapTest: XCTestCase {
             map(\.string, equal("world"))
         ))
     }
+
+    // MARK: Compact map
+    func testCompactMap() {
+        expect("1").to(compactMap({ Int($0) }, equal(1)))
+        expect("1").toNot(compactMap({ Int($0) }, equal(2)))
+
+        let assertions = gatherExpectations(silently: true) {
+            expect("not a number").to(compactMap({ Int($0) }, equal(1)))
+            expect("not a number").toNot(compactMap({ Int($0) }, equal(1)))
+        }
+
+        expect(assertions).to(haveCount(2))
+        expect(assertions.first?.success).to(beFalse())
+        expect(assertions.last?.success).to(beFalse())
+    }
+
+    func testCompactMapAsync() async {
+        struct Value {
+            let int: Int?
+            let string: String?
+        }
+
+        await expect("1").to(compactMap({ Int($0) }, asyncEqual(1)))
+        await expect("1").toNot(compactMap({ Int($0) }, asyncEqual(2)))
+
+        let assertions = await gatherExpectations(silently: true) {
+            await expect("not a number").to(compactMap({ Int($0) }, asyncEqual(1)))
+            await expect("not a number").toNot(compactMap({ Int($0) }, asyncEqual(1)))
+        }
+
+        expect(assertions).to(haveCount(2))
+        expect(assertions.first?.success).to(beFalse())
+        expect(assertions.last?.success).to(beFalse())
+    }
+
+    func testCompactMapWithAsyncFunction() async {
+        func someOperation(_ value: Int) async -> String? {
+            "\(value)"
+        }
+        await expect(1).to(compactMap(someOperation, equal("1")))
+
+        func someFailingOperation(_ value: Int) async -> String? {
+            nil
+        }
+
+        let assertions = await gatherExpectations(silently: true) {
+            await expect(1).to(compactMap(someFailingOperation, equal("1")))
+            await expect(1).toNot(compactMap(someFailingOperation, equal("1")))
+        }
+
+        expect(assertions).to(haveCount(2))
+        expect(assertions.first?.success).to(beFalse())
+        expect(assertions.last?.success).to(beFalse())
+    }
+
+    func testCompactMapWithActor() {
+        actor Box {
+            let int: Int?
+            let string: String?
+
+            init(int: Int?, string: String?) {
+                self.int = int
+                self.string = string
+            }
+        }
+
+        let box = Box(int: 3, string: "world")
+
+        expect(box).to(satisfyAllOf(
+            compactMap(\.int, equal(3)),
+            compactMap(\.string, equal("world"))
+        ))
+
+        let failingBox = Box(int: nil, string: nil)
+
+        let assertions = gatherExpectations(silently: true) {
+            expect(failingBox).to(satisfyAllOf(
+                compactMap(\.int, equal(3))
+            ))
+            expect(failingBox).toNot(satisfyAllOf(
+                compactMap(\.int, equal(3))
+            ))
+        }
+        expect(assertions).to(haveCount(2))
+        expect(assertions.first?.success).to(beFalse())
+        expect(assertions.last?.success).to(beFalse())
+    }
 }