Add Rescue methods

bfriesen · Apr 17, 2023 · 2a7ebaf · 2a7ebaf
1 parent 89795e3
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning].
 
 - RandomSkunk.Results:
     - Add `Maybe<T>.ToFailIfNone` method.
+    - Add `Rescue` methods.
 
 ### Fixed
 - RandomSkunk.Results:

diff --git a/RandomSkunk.Results.UnitTests/Rescue_methods.cs b/RandomSkunk.Results.UnitTests/Rescue_methods.cs
@@ -0,0 +1,290 @@
+namespace RandomSkunk.Results.UnitTests;
+
+public class Rescue_methods
+{
+    public class For_Result_sync
+    {
+        [Fact]
+        public void Given_IsSuccess_Returns_source()
+        {
+            var sourceResult = Result.Success();
+            var rescueResult = Result.Fail();
+
+            var actual = sourceResult.Rescue(error => rescueResult);
+
+            actual.Should().Be(sourceResult);
+        }
+
+        [Fact]
+        public void Given_IsFail_Returns_result_from_rescue_function()
+        {
+            var sourceResult = Result.Fail();
+            var rescueResult = Result.Success();
+            Error? capturedError = null;
+
+            var actual = sourceResult.Rescue(error =>
+            {
+                capturedError = error;
+                return rescueResult;
+            });
+
+            actual.Should().Be(rescueResult);
+            capturedError.Should().Be(sourceResult.Error);
+        }
+
+        [Fact]
+        public void Given_IsFail_When_rescue_function_throws_Returns_result_from_caught_exception()
+        {
+            var sourceResult = Result.Fail();
+            var thrownException = new Exception();
+
+            var actual = sourceResult.Rescue((Func<Error, Result>)(error => throw thrownException));
+
+            actual.IsFail.Should().BeTrue();
+            actual.Error.ErrorCode.Should().Be(ErrorCodes.CaughtException);
+            actual.Error.InnerError!.Title.Should().Be(nameof(Exception));
+        }
+    }
+
+    public class For_Result_async
+    {
+        [Fact]
+        public async Task Given_IsSuccess_Returns_source()
+        {
+            var sourceResult = Result.Success();
+            var rescueResult = Result.Fail();
+
+            var actual = await sourceResult.Rescue(error => Task.FromResult(rescueResult));
+
+            actual.Should().Be(sourceResult);
+        }
+
+        [Fact]
+        public async Task Given_IsFail_Returns_result_from_rescue_function()
+        {
+            var sourceResult = Result.Fail();
+            var rescueResult = Result.Success();
+            Error? capturedError = null;
+
+            var actual = await sourceResult.Rescue(error =>
+            {
+                capturedError = error;
+                return Task.FromResult(rescueResult);
+            });
+
+            actual.Should().Be(rescueResult);
+            capturedError.Should().Be(sourceResult.Error);
+        }
+
+        [Fact]
+        public async Task Given_IsFail_When_rescue_function_throws_Returns_result_from_caught_exception()
+        {
+            var sourceResult = Result.Fail();
+            var thrownException = new Exception();
+
+            var actual = await sourceResult.Rescue((Func<Error, Task<Result>>)(error => throw thrownException));
+
+            actual.IsFail.Should().BeTrue();
+            actual.Error.ErrorCode.Should().Be(ErrorCodes.CaughtException);
+            actual.Error.InnerError!.Title.Should().Be(nameof(Exception));
+        }
+    }
+
+    public class For_Result_of_T_sync
+    {
+        [Fact]
+        public void Given_IsSuccess_Returns_source()
+        {
+            var sourceResult = Result<int>.Success(123);
+            var rescueResult = Result<int>.Fail();
+
+            var actual = sourceResult.Rescue(error => rescueResult);
+
+            actual.Should().Be(sourceResult);
+        }
+
+        [Fact]
+        public void Given_IsFail_Returns_result_from_rescue_function()
+        {
+            var sourceResult = Result<int>.Fail();
+            var rescueResult = Result<int>.Success(123);
+            Error? capturedError = null;
+
+            var actual = sourceResult.Rescue(error =>
+            {
+                capturedError = error;
+                return rescueResult;
+            });
+
+            actual.Should().Be(rescueResult);
+            capturedError.Should().Be(sourceResult.Error);
+        }
+
+        [Fact]
+        public void Given_IsFail_When_rescue_function_throws_Returns_result_from_caught_exception()
+        {
+            var sourceResult = Result<int>.Fail();
+            var thrownException = new Exception();
+
+            var actual = sourceResult.Rescue((Func<Error, Result<int>>)(error => throw thrownException));
+
+            actual.IsFail.Should().BeTrue();
+            actual.Error.ErrorCode.Should().Be(ErrorCodes.CaughtException);
+            actual.Error.InnerError!.Title.Should().Be(nameof(Exception));
+        }
+    }
+
+    public class For_Result_of_T_async
+    {
+        [Fact]
+        public async Task Given_IsSuccess_Returns_source()
+        {
+            var sourceResult = Result<int>.Success(123);
+            var rescueResult = Result<int>.Fail();
+
+            var actual = await sourceResult.Rescue(error => Task.FromResult(rescueResult));
+
+            actual.Should().Be(sourceResult);
+        }
+
+        [Fact]
+        public async Task Given_IsFail_Returns_result_from_rescue_function()
+        {
+            var sourceResult = Result<int>.Fail();
+            var rescueResult = Result<int>.Success(123);
+            Error? capturedError = null;
+
+            var actual = await sourceResult.Rescue(error =>
+            {
+                capturedError = error;
+                return Task.FromResult(rescueResult);
+            });
+
+            actual.Should().Be(rescueResult);
+            capturedError.Should().Be(sourceResult.Error);
+        }
+
+        [Fact]
+        public async Task Given_IsFail_When_rescue_function_throws_Returns_result_from_caught_exception()
+        {
+            var sourceResult = Result<int>.Fail();
+            var thrownException = new Exception();
+
+            var actual = await sourceResult.Rescue((Func<Error, Task<Result<int>>>)(error => throw thrownException));
+
+            actual.IsFail.Should().BeTrue();
+            actual.Error.ErrorCode.Should().Be(ErrorCodes.CaughtException);
+            actual.Error.InnerError!.Title.Should().Be(nameof(Exception));
+        }
+    }
+
+    public class For_Maybe_of_T_sync
+    {
+        [Fact]
+        public void Given_IsSuccess_Returns_source()
+        {
+            var sourceResult = Maybe<int>.Success(123);
+            var rescueResult = Maybe<int>.Fail();
+
+            var actual = sourceResult.Rescue(error => rescueResult);
+
+            actual.Should().Be(sourceResult);
+        }
+
+        [Fact]
+        public void Given_None_Returns_source()
+        {
+            var sourceResult = Maybe<int>.None;
+            var rescueResult = Maybe<int>.Fail();
+
+            var actual = sourceResult.Rescue(error => rescueResult);
+
+            actual.Should().Be(sourceResult);
+        }
+
+        [Fact]
+        public void Given_IsFail_Returns_result_from_rescue_function()
+        {
+            var sourceResult = Maybe<int>.Fail();
+            var rescueResult = Maybe<int>.Success(123);
+            Error? capturedError = null;
+
+            var actual = sourceResult.Rescue(error =>
+            {
+                capturedError = error;
+                return rescueResult;
+            });
+
+            actual.Should().Be(rescueResult);
+            capturedError.Should().Be(sourceResult.Error);
+        }
+
+        [Fact]
+        public void Given_IsFail_When_rescue_function_throws_Returns_result_from_caught_exception()
+        {
+            var sourceResult = Maybe<int>.Fail();
+            var thrownException = new Exception();
+
+            var actual = sourceResult.Rescue((Func<Error, Maybe<int>>)(error => throw thrownException));
+
+            actual.IsFail.Should().BeTrue();
+            actual.Error.ErrorCode.Should().Be(ErrorCodes.CaughtException);
+            actual.Error.InnerError!.Title.Should().Be(nameof(Exception));
+        }
+    }
+
+    public class For_Maybe_of_T_async
+    {
+        [Fact]
+        public async Task Given_IsSuccess_Returns_source()
+        {
+            var sourceResult = Maybe<int>.Success(123);
+            var rescueResult = Maybe<int>.Fail();
+
+            var actual = await sourceResult.Rescue(error => Task.FromResult(rescueResult));
+
+            actual.Should().Be(sourceResult);
+        }
+
+        [Fact]
+        public async Task Given_IsNone_Returns_source()
+        {
+            var sourceResult = Maybe<int>.None;
+            var rescueResult = Maybe<int>.Fail();
+
+            var actual = await sourceResult.Rescue(error => Task.FromResult(rescueResult));
+
+            actual.Should().Be(sourceResult);
+        }
+
+        [Fact]
+        public async Task Given_IsFail_Returns_result_from_rescue_function()
+        {
+            var sourceResult = Maybe<int>.Fail();
+            var rescueResult = Maybe<int>.Success(123);
+            Error? capturedError = null;
+
+            var actual = await sourceResult.Rescue(error =>
+            {
+                capturedError = error;
+                return Task.FromResult(rescueResult);
+            });
+
+            actual.Should().Be(rescueResult);
+            capturedError.Should().Be(sourceResult.Error);
+        }
+
+        [Fact]
+        public async Task Given_IsFail_When_rescue_function_throws_Returns_result_from_caught_exception()
+        {
+            var sourceResult = Maybe<int>.Fail();
+            var thrownException = new Exception();
+
+            var actual = await sourceResult.Rescue((Func<Error, Task<Maybe<int>>>)(error => throw thrownException));
+
+            actual.IsFail.Should().BeTrue();
+            actual.Error.ErrorCode.Should().Be(ErrorCodes.CaughtException);
+            actual.Error.InnerError!.Title.Should().Be(nameof(Exception));
+        }
+    }
+}