Fix codefix for array length 0 or 1 (#73)

Author: cbersch

src/AwesomeAssertions.Analyzers.Tests/Tips/CollectionTests.cs

@@ -309,6 +309,12 @@ public class CollectionTests
         [Implemented]
         public void CollectionShouldHaveCount_CountShouldBe0_TestAnalyzer(string assertion) => VerifyCSharpDiagnosticCodeBlock(assertion, DiagnosticMetadata.CollectionShouldBeEmpty_CountShouldBe0);
 
+        [TestMethod]
+        [AssertionDiagnostic("actual.Length.Should().Be(0{0});")]
+        [AssertionDiagnostic("actual.ToArray().Length.Should().Be(0{0}).And.ToString();")]
+        [Implemented]
+        public void CollectionShouldHaveCount_LengthShouldBe0_TestAnalyzer(string assertion) => VerifyArrayCSharpDiagnosticCodeBlock(assertion, DiagnosticMetadata.CollectionShouldBeEmpty_LengthShouldBe0);
+
         [TestMethod]
         [AssertionDiagnostic("actual.Count().Should().Be(1{0});")]
         [AssertionDiagnostic("actual.AsEnumerable().Count().Should().Be(1{0}).And.ToString();")]
@@ -317,6 +323,12 @@ public class CollectionTests
         [Implemented]
         public void CollectionShouldHaveCount_CountShouldBe1_TestAnalyzer(string assertion) => VerifyCSharpDiagnosticCodeBlock(assertion, DiagnosticMetadata.CollectionShouldContainSingle_CountShouldBe1);
 
+        [TestMethod]
+        [AssertionDiagnostic("actual.Length.Should().Be(1{0});")]
+        [AssertionDiagnostic("actual.ToArray().Length.Should().Be(1{0}).And.ToString();")]
+        [Implemented]
+        public void CollectionShouldHaveCount_ArrayLengthShouldBe1_TestAnalyzer(string assertion) => VerifyArrayCSharpDiagnosticCodeBlock(assertion, DiagnosticMetadata.CollectionShouldContainSingle_LengthShouldBe1);
+
         [TestMethod]
         [AssertionDiagnostic("(array.Count() + 1).Should().Be(0{0}).And.ToString();")]
         [AssertionDiagnostic("(array.Count() + 1).Should().Be(1{0}).And.ToString();")]
@@ -394,9 +406,15 @@ public void CollectionShouldHaveCount_LengthShouldBe_TestNoAnalyzer(string asser
         [AssertionCodeFix(
             oldAssertion: "actual.ToList().Count.Should().Be(0{0});",
             newAssertion: "actual.ToList().Should().BeEmpty({0});")]
+        [AssertionCodeFix(
+            oldAssertion: "actual.ToArray().Length.Should().Be(0{0});",
+            newAssertion: "actual.ToArray().Should().BeEmpty({0});")]
         [AssertionCodeFix(
             oldAssertion: "actual.ToList().Count.Should().Be(1{0});",
             newAssertion: "actual.ToList().Should().ContainSingle({0});")]
+        [AssertionCodeFix(
+            oldAssertion: "actual.ToArray().Length.Should().Be(1{0});",
+            newAssertion: "actual.ToArray().Should().ContainSingle({0});")]
         [AssertionCodeFix(
             oldAssertion: "actual.ToList().Count.Should().Be(6{0});",
             newAssertion: "actual.ToList().Should().HaveCount(6{0});")]

src/AwesomeAssertions.Analyzers/Tips/AwesomeAssertionsAnalyzer.cs

@@ -339,7 +339,18 @@ private static void AnalyzeInvocation(OperationAnalysisContext context, AwesomeA
                         switch (propertyBeforeShould.Property.Name)
                         {
                             case nameof(Array.Length) when propertyBeforeShould.IsContainedInType(SpecialType.System_Array) && propertyBeforeShould.Instance.Type is IArrayTypeSymbol { Rank: 1 }:
-                                context.ReportDiagnostic(CreateDiagnostic(assertion, DiagnosticMetadata.CollectionShouldHaveCount_LengthShouldBe));
+                                if (assertion.Arguments[0].IsLiteralValue(1))
+                                {
+                                    context.ReportDiagnostic(CreateDiagnostic(assertion, DiagnosticMetadata.CollectionShouldContainSingle_LengthShouldBe1));
+                                }
+                                else if (assertion.Arguments[0].IsLiteralValue(0))
+                                {
+                                    context.ReportDiagnostic(CreateDiagnostic(assertion, DiagnosticMetadata.CollectionShouldBeEmpty_LengthShouldBe0));
+                                }
+                                else
+                                {
+                                    context.ReportDiagnostic(CreateDiagnostic(assertion, DiagnosticMetadata.CollectionShouldHaveCount_LengthShouldBe));
+                                }
                                 return;
                             case nameof(string.Length) when propertyBeforeShould.IsContainedInType(SpecialType.System_String):
                                 context.ReportDiagnostic(CreateDiagnostic(assertion, DiagnosticMetadata.StringShouldHaveLength_LengthShouldBe));

src/AwesomeAssertions.Analyzers/Tips/AwesomeAssertionsCodeFixProvider.cs

@@ -134,12 +134,14 @@ CreateChangedDocument RemoveExpressionBeforeShouldAndRenameAssertionWithoutFirst
                     }
                 ]);
             case nameof(DiagnosticMetadata.CollectionShouldBeEmpty_CountPropertyShouldBe0):
+            case nameof(DiagnosticMetadata.CollectionShouldBeEmpty_LengthShouldBe0):
                 return RemoveExpressionBeforeShouldAndRenameAssertionWithoutFirstArgumentWithArgumentsFromRemoved("BeEmpty");
             case nameof(DiagnosticMetadata.CollectionShouldBeEmpty_CountShouldBe0):
                 return RemoveMethodBeforeShouldAndRenameAssertionWithoutFirstArgumentWithArgumentsFromRemoved("BeEmpty");
             case nameof(DiagnosticMetadata.CollectionShouldContainSingle_CountShouldBe1):
                 return RemoveMethodBeforeShouldAndRenameAssertionWithoutFirstArgumentWithArgumentsFromRemoved("ContainSingle");
             case nameof(DiagnosticMetadata.CollectionShouldContainSingle_CountPropertyShouldBe1):
+            case nameof(DiagnosticMetadata.CollectionShouldContainSingle_LengthShouldBe1):
                 return RemoveExpressionBeforeShouldAndRenameAssertionWithoutFirstArgumentWithArgumentsFromRemoved("ContainSingle");
             case nameof(DiagnosticMetadata.CollectionShouldHaveCount_CountShouldBe):
                 return RemoveExpressionBeforeShouldAndRenameAssertion("HaveCount");

src/AwesomeAssertions.Analyzers/Tips/DiagnosticMetadata.cs

@@ -35,9 +35,11 @@ private DiagnosticMetadata(string message, string helpLink, [CallerMemberName] s
     public static DiagnosticMetadata CollectionShouldContainSingle_ShouldHaveCount1 { get; } = new("Use .Should().ContainSingle()", GetHelpLink("Collections-15"));
     public static DiagnosticMetadata CollectionShouldContainSingle_CountShouldBe1 { get; } = new("Use .Should().ContainSingle()", GetHelpLink("Collections-15"));
     public static DiagnosticMetadata CollectionShouldContainSingle_CountPropertyShouldBe1 { get; } = new("Use .Should().ContainSingle()", GetHelpLink("Collections-15"));
+    public static DiagnosticMetadata CollectionShouldContainSingle_LengthShouldBe1 { get; } = new("Use .Should().ContainSingle()", GetHelpLink("Collections-15"));
     public static DiagnosticMetadata CollectionShouldBeEmpty_ShouldHaveCount0 { get; } = new("Use .Should().BeEmpty()", GetHelpLink("Collections-16"));
     public static DiagnosticMetadata CollectionShouldBeEmpty_CountShouldBe0 { get; } = new("Use .Should().BeEmpty()", GetHelpLink("Collections-16"));
     public static DiagnosticMetadata CollectionShouldBeEmpty_CountPropertyShouldBe0 { get; } = new("Use .Should().BeEmpty()", GetHelpLink("Collections-16"));
+    public static DiagnosticMetadata CollectionShouldBeEmpty_LengthShouldBe0 { get; } = new("Use .Should().BeEmpty()", GetHelpLink("Collections-16"));
     public static DiagnosticMetadata CollectionShouldHaveSameCount_ShouldHaveCountOtherCollectionCount { get; } = new("Use .Should().HaveSameCount()", GetHelpLink("Collections-17"));
     public static DiagnosticMetadata CollectionShouldNotHaveSameCount_CountShouldNotBeOtherCollectionCount { get; } = new("Use .Should().NotHaveSameCount()", GetHelpLink("Collections-18"));
     public static DiagnosticMetadata CollectionShouldContainProperty_WhereShouldNotBeEmpty { get; } = new("Use .Should().Contain()", GetHelpLink("Collections-19"));