Result.init(catching:) with async method (#2060)

I ended up not using this in my recent PR but it's a useful overload.

Sources/FoundationExtensions/Result+Extensions.swift

@@ -71,3 +71,17 @@ extension Result where Success: OptionalType {
     }
 
 }
+
+@available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.2, *)
+extension Result where Failure == Swift.Error {
+
+    /// Equivalent to `Result.init(catching:)` but with an `async` closure.
+    init(catching block: () async throws -> Success) async {
+        do {
+            self = .success(try await block())
+        } catch {
+            self = .failure(error)
+        }
+    }
+
+}

Tests/UnitTests/FoundationExtensions/ResultExtensionsTests.swift

@@ -69,6 +69,36 @@ class ResultExtensionsTests: TestCase {
         })
     }
 
+    @available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.2, *)
+    func testInitWithThrowingAsyncBlockReturningValue() async throws {
+        try AvailabilityChecks.iOS13APIAvailableOrSkipTest()
+
+        let expectedValue: Int = .random(in: 0..<100)
+
+        func asyncValue() async throws -> Int {
+            return expectedValue
+        }
+
+        let result: Result<Int, Swift.Error> = await .init(catching: { try await asyncValue() })
+        expect(result).to(beSuccess())
+        expect(result.value) == expectedValue
+    }
+
+    @available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.2, *)
+    func testInitWithThrowingAsyncBlockThrowingError() async throws {
+        try AvailabilityChecks.iOS13APIAvailableOrSkipTest()
+
+        let expectedError: ErrorCode = .customerInfoError
+
+        func asyncValue() async throws -> Int {
+            throw expectedError
+        }
+
+        let result: Result<Int, Swift.Error> = await .init(catching: { try await asyncValue() })
+        expect(result).to(beFailure())
+        expect(result.error).to(matchError(expectedError))
+    }
+
 }
 
 class ResultAsOptionalResultTest: TestCase {