Fix assertions for With/Without test methods when there are multiple …

…failures (#1937) (#1938)

* Apply validation predicate to matched entries only for Without*** worked correctly when there is more than one failure
* Apply validation predicate only to matched entries for With*** assertions too to correctly display failures

src/FluentValidation.Tests/ValidatorTesterTester.cs

@@ -469,6 +469,57 @@ public class ValidatorTesterTester {
 				ex.Message.ShouldEqual("Found an unexpected error code of 'bar'");
 		}
 
+		[Fact]
+		public void Expected_without_error_code_check() {
+			//#1937
+			var validator = new InlineValidator<Person> {
+				v => v.RuleFor(x => x.Surname).NotNull(),
+				v => v.RuleFor(x => x.Forename).NotNull()
+			};
+
+			validator.TestValidate(new Person())
+				.ShouldHaveValidationErrorFor(x => x.Surname)
+				.WithoutErrorCode("foo")
+				.WithoutErrorMessage("bar")
+				.WithoutSeverity(Severity.Warning)
+				.WithoutCustomState(1);
+		}
+
+		[Fact]
+		public void Unexpected_with_error_message_check() {
+			//#1937
+			var validator = new InlineValidator<Person>
+			{
+				v => v.RuleFor(x => x.Forename).NotEmpty(),
+				v => v.RuleFor(x => x.Surname).NotEmpty()
+			};
+
+			var ex = Assert.Throws<ValidationTestException>(() =>
+				validator.TestValidate(new Person())
+					.ShouldHaveValidationErrorFor(x => x.Surname)
+					.WithErrorMessage("bar"));
+			ex.Message.ShouldEqual("Expected an error message of 'bar'. Actual message was ''Surname' must not be empty.'");
+		}
+
+		[Fact]
+		public void Expected_with_error_code_check() {
+			var validator = new InlineValidator<Person> {
+				v => v.RuleFor(x => x.Forename).NotNull(),
+				v => v.RuleFor(x => x.Surname).NotNull()
+					.WithErrorCode("foo")
+					.WithMessage("bar")
+					.WithSeverity(Severity.Warning)
+					.WithState(_ => 1)
+			};
+
+			validator.TestValidate(new Person())
+				.ShouldHaveValidationErrorFor(x => x.Surname)
+				.WithErrorCode("foo")
+				.WithErrorMessage("bar")
+				.WithSeverity(Severity.Warning)
+				.WithCustomState(1);
+		}
+
 		[Fact]
 		public void Expected_severity_check() {
 			var validator = new InlineValidator<Person> {

src/FluentValidation/TestHelper/ValidatorTestExtensions.cs

@@ -184,7 +184,7 @@ public static class ValidationTestExtension {
 		}
 
 		public static ITestValidationWith When(this ITestValidationContinuation failures, Func<ValidationFailure, bool> failurePredicate, string exceptionMessage = null) {
-			var result = TestValidationContinuation.Create(failures);
+			var result = TestValidationContinuation.Create(((TestValidationContinuation)failures).MatchedFailures);
 			result.ApplyPredicate(failurePredicate);
 
 			var anyMatched = result.Any();
@@ -198,7 +198,7 @@ public static class ValidationTestExtension {
 		}
 
 		public static ITestValidationContinuation WhenAll(this ITestValidationContinuation failures, Func<ValidationFailure, bool> failurePredicate, string exceptionMessage = null) {
-			var result = TestValidationContinuation.Create(failures);
+			var result = TestValidationContinuation.Create(((TestValidationContinuation)failures).MatchedFailures);
 			result.ApplyPredicate(failurePredicate);
 
 			bool allMatched = !result.UnmatchedFailures.Any();