Add proper mocking of HttpClient in HgServiceTests

This allows us to uncomment the tests we were skipping earlier, because
now we can mock HttpClient and not allow HgService to hit the network
during unit tests.

backend/Testing/LexCore/Services/HgServiceTests.cs

@@ -7,6 +7,7 @@
 using Microsoft.Extensions.Logging.Abstractions;
 using Microsoft.Extensions.Options;
 using Moq;
+using Moq.Contrib.HttpClient;
 using Shouldly;
 using Testing.Fixtures;
 
@@ -30,8 +31,16 @@ public HgServiceTests()
             HgResumableUrl = LexboxResumable,
             SendReceiveDomain = LexboxHgWeb
         };
+        var handler = new Mock<HttpMessageHandler>(MockBehavior.Strict);
+
+        // This may need to become more sophisticated if our FinishReset tests are changed to include
+        // a Mercurial repo with actual commits in it, but this is good enough at the moment.
+        var AllZeroHash = "0000000000000000000000000000000000000000";
+        handler.SetupAnyRequest().ReturnsResponse(AllZeroHash);
+
+        var mockFactory = handler.CreateClientFactory();
         _hgService = new HgService(new OptionsWrapper<HgConfig>(_hgConfig),
-            Mock.Of<IHttpClientFactory>(),
+            mockFactory,
             NullLogger<HgService>.Instance);
         CleanUpTempDir();
     }
@@ -53,9 +62,9 @@ public void DetermineProjectPrefixWorks(HgType type, string expectedUrl)
         HgService.DetermineProjectUrlPrefix(type, _hgConfig).ShouldBe(expectedUrl);
     }
 
-    // [Theory]
-    // [InlineData(".hg/important-file.bin")]
-    // [InlineData("unzip-test/.hg/important-file.bin")]
+    [Theory]
+    [InlineData(".hg/important-file.bin")]
+    [InlineData("unzip-test/.hg/important-file.bin")]
     public async Task CanFinishResetByUnZippingAnArchive(string filePath)
     {
         // arrange
@@ -98,7 +107,7 @@ private void CreateSimpleEntry(ZipArchive zipArchive, string filePath)
         fileStream.Flush();
     }
 
-    // [Fact]
+    [Fact]
     public async Task ThrowsIfNoHgFolderIsFound()
     {
         var code = "unzip-test-no-hg";

backend/Testing/Testing.csproj

@@ -15,6 +15,7 @@
     <Choose>
         <When Condition=" '$(MercurialVersion)' == '6' ">
             <ItemGroup>
+                <PackageReference Include="Moq.Contrib.HttpClient" Version="1.4.0" />
                 <PackageReference Include="SIL.Chorus.LibChorus" Version="6.0.0-beta0046" />
                 <PackageReference Include="SIL.Chorus.Mercurial" Version="6.*" />
             </ItemGroup>