Add the command line option `--output-pinvokes` (#992)

* Add the command line option `--output-pinvokes`

* Remove unnecessary memory stream

* Address feedback

* Sort list of pinvokes, add unreachable DllImports to the tests

* Remove redundant if, change comparison order of PInvokeInfo

* Use an overload of Zip that is compatible with .NET 4.7.71

* Use StringComparison.Ordinal when comparing PInvokeInfo fields
Use List for storing PInvokeInfos

* Copy PInvokes json to tests output directory

3 files changed, 67 insertions, 2 deletions

diff --git a/test/Mono.Linker.Tests/Mono.Linker.Tests.csproj b/test/Mono.Linker.Tests/Mono.Linker.Tests.csproj
index e4b13a53c..2e93533ee 100644
--- a/test/Mono.Linker.Tests/Mono.Linker.Tests.csproj
+++ b/test/Mono.Linker.Tests/Mono.Linker.Tests.csproj
@@ -64,6 +64,12 @@
     <PackageReference Include="NUnit3TestAdapter" Version="3.10.0" />
   </ItemGroup>
 
+  <ItemGroup>
+    <None Update="TestCases\Dependencies\PInvokesExpectations.json">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+
   <Target Name="RunTestsOnMono" Condition="'$(MonoBuild)' != ''">
     <Exec Command="mono $(PkgNUnit_ConsoleRunner)/tools/nunit3-console.exe --result=TestResults.xml $(OutputPath)Mono.Linker.Tests.dll" />
   </Target>
@@ -72,8 +78,7 @@
 
   <!-- Arcade's custom test imports assume that we are using xunit. -->
   <!-- Map the Arcade "Test" target to the "VSTest" target used by "dotnet test" -->
-  <Target Name="Test"
-          Condition="'$(MonoBuild)' == ''">
+  <Target Name="Test" Condition="'$(MonoBuild)' == ''">
     <MSBuild Projects="$(MSBuildProjectFile)" Targets="VSTest" />
   </Target>
 
diff --git a/test/Mono.Linker.Tests/TestCases/Dependencies/PInvokesExpectations.json b/test/Mono.Linker.Tests/TestCases/Dependencies/PInvokesExpectations.json
new file mode 100644
index 000000000..872915eca
--- /dev/null
+++ b/test/Mono.Linker.Tests/TestCases/Dependencies/PInvokesExpectations.json
@@ -0,0 +1,32 @@
+[
+    {
+        "assembly": "copyassembly.dll",
+        "entryPoint": "CustomEntryPoint",
+        "fullName": "Mono.Linker.Tests.Cases.Interop.PInvoke.Individual.Dependencies.CanOutputPInvokes_CopyAssembly Mono.Linker.Tests.Cases.Interop.PInvoke.Individual.Dependencies.CanOutputPInvokes_CopyAssembly::CustomEntryPoint()",
+        "moduleName": "lib_copyassembly"
+    },
+    {
+        "assembly": "copyassembly.dll",
+        "entryPoint": "FooEntryPoint",
+        "fullName": "Mono.Linker.Tests.Cases.Interop.PInvoke.Individual.Dependencies.CanOutputPInvokes_CopyAssembly Mono.Linker.Tests.Cases.Interop.PInvoke.Individual.Dependencies.CanOutputPInvokes_CopyAssembly::FooEntryPoint()",
+        "moduleName": "lib_copyassembly"
+    },
+    {
+        "assembly": "test.exe",
+        "entryPoint": "CustomEntryPoint",
+        "fullName": "Mono.Linker.Tests.Cases.Interop.PInvoke.Individual.CanOutputPInvokes\/Foo Mono.Linker.Tests.Cases.Interop.PInvoke.Individual.CanOutputPInvokes::CustomEntryPoint()",
+        "moduleName": "lib"
+    },
+    {
+        "assembly": "test.exe",
+        "entryPoint": "CustomEntryPoint",
+        "fullName": "Mono.Linker.Tests.Cases.Interop.PInvoke.Individual.CanOutputPInvokes\/Foo Mono.Linker.Tests.Cases.Interop.PInvoke.Individual.CanOutputPInvokes::CustomEntryPoint0()",
+        "moduleName": "lib"
+    },
+    {
+        "assembly": "test.exe",
+        "entryPoint": "FooEntryPoint",
+        "fullName": "Mono.Linker.Tests.Cases.Interop.PInvoke.Individual.CanOutputPInvokes\/Foo Mono.Linker.Tests.Cases.Interop.PInvoke.Individual.CanOutputPInvokes::FooEntryPoint()",
+        "moduleName": "lib"
+    }
+]
\ No newline at end of file
diff --git a/test/Mono.Linker.Tests/TestCases/IndividualTests.cs b/test/Mono.Linker.Tests/TestCases/IndividualTests.cs
index 439caf37e..7ded3ee80 100644
--- a/test/Mono.Linker.Tests/TestCases/IndividualTests.cs
+++ b/test/Mono.Linker.Tests/TestCases/IndividualTests.cs
@@ -1,12 +1,18 @@
 using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Runtime.Serialization.Json;
 using System.Xml;
 using Mono.Cecil;
 using Mono.Linker.Tests.Cases.CommandLine.Mvid;
+using Mono.Linker.Tests.Cases.Interop.PInvoke.Individual;
 using Mono.Linker.Tests.Cases.References.Individual;
 using Mono.Linker.Tests.Cases.Tracing.Individual;
 using Mono.Linker.Tests.Extensions;
 using Mono.Linker.Tests.TestCasesRunner;
 using NUnit.Framework;
+using NUnit.Framework.Internal;
 
 namespace Mono.Linker.Tests.TestCases
 {
@@ -27,6 +33,28 @@ namespace Mono.Linker.Tests.TestCases
 		}
 
 		[Test]
+		public void CanOutputPInvokes ()
+		{
+			var testcase = CreateIndividualCase (typeof (CanOutputPInvokes));
+			var result = Run (testcase);
+
+			var outputPath = result.OutputAssemblyPath.Parent.Combine ("pinvokes.json");
+			if (!outputPath.Exists ())
+				Assert.Fail ($"The json file with the list of all the PInvokes found by the linker is missing. Expected it to exist at {outputPath}");
+
+			var jsonSerializer = new DataContractJsonSerializer (typeof (List<PInvokeInfo>));
+
+			using (var fsActual = File.Open(outputPath, FileMode.Open))
+			using (var fsExpected = File.Open("TestCases/Dependencies/PInvokesExpectations.json", FileMode.Open)) {
+				var actual = jsonSerializer.ReadObject (fsActual) as List<PInvokeInfo>;
+				var expected = jsonSerializer.ReadObject (fsExpected) as List<PInvokeInfo>;
+				foreach (var pinvokePair in Enumerable.Zip(actual, expected, (fst, snd) => Tuple.Create(fst, snd))) {
+					Assert.That (pinvokePair.Item1.CompareTo (pinvokePair.Item2), Is.EqualTo (0));
+				}
+			}
+		}
+
+		[Test]
 		public void CanEnableDependenciesDump ()
 		{
 			var testcase = CreateIndividualCase (typeof (CanEnableDependenciesDump));