Add basic dotnet test failure integration test

buildpacks/dotnet/tests/dotnet_test_test.rs

@@ -40,3 +40,22 @@ fn test_dotnet_test_success() {
         },
     );
 }
+
+#[test]
+#[ignore = "integration test"]
+fn test_dotnet_test_failure() {
+    TestRunner::default().build(
+        default_build_config("tests/fixtures/xunit_project_fail")
+            .env("DOTNET_SDK_COMMAND", "test")
+            .expected_pack_result(libcnb_test::PackResult::Failure),
+        |context| {
+            assert_contains!(
+                context.pack_stdout,
+                "- Detected .NET file to test: `/workspace/foo.csproj`"
+            );
+            assert_contains!(
+                context.pack_stdout,
+                "Failed!  - Failed:     1, Passed:     0, Skipped:     0, Total:     1, Duration: < 1 ms - foo.dll (net8.0)");
+        },
+    );
+}

buildpacks/dotnet/tests/fixtures/xunit_project_fail/FooTests.cs

@@ -0,0 +1,10 @@
+namespace foo;
+
+public class FooTests
+{
+    [Fact]
+    public void FooEqualsFoo()
+    {
+        Assert.Equal("foo", "bar");
+    }
+}

buildpacks/dotnet/tests/fixtures/xunit_project_fail/foo.csproj

@@ -0,0 +1,23 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+
+    <IsPackable>false</IsPackable>
+    <IsTestProject>true</IsTestProject>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" Version="6.0.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
+    <PackageReference Include="xunit" Version="2.5.3" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.3" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="Xunit" />
+  </ItemGroup>
+
+</Project>

buildpacks/dotnet/tests/fixtures/xunit_project_fail/global.json

@@ -0,0 +1,6 @@
+{
+    "sdk": {
+        "version": "8.0.101",
+        "rollForward": "disable"
+    }
+}