Assert our tests don't accidentally have compiler errors in them

This is just to prevent tests from not doing what we expected them to
do for the reason we thought.

src/Features/Lsif/GeneratorTest/RangeResultSetTests.vb

@@ -13,9 +13,9 @@ Namespace Microsoft.CodeAnalysis.LanguageServerIndexFormat.Generator.UnitTests
 
         <Theory>
         <InlineData("class C { [|string|] s; }", "mscorlib#T:System.String", WellKnownSymbolMonikerSchemes.DotnetXmlDoc)>
-        <InlineData("class C { void M() { [|M|](); }", TestProjectAssemblyName + "#M:C.M", WellKnownSymbolMonikerSchemes.DotnetXmlDoc)>
-        <InlineData("class C { void M(string s) { M([|s|]) }", TestProjectAssemblyName + "#M:C.M(System.String)#s", WellKnownSymbolMonikerSchemes.DotnetXmlDoc)>
-        <InlineData("class C { void M(string s) { string local; M([|local|]) }", Nothing, Nothing)>
+        <InlineData("class C { void M() { [|M|](); } }", TestProjectAssemblyName + "#M:C.M", WellKnownSymbolMonikerSchemes.DotnetXmlDoc)>
+        <InlineData("class C { void M(string s) { M([|s|]); } }", TestProjectAssemblyName + "#M:C.M(System.String)#s", WellKnownSymbolMonikerSchemes.DotnetXmlDoc)>
+        <InlineData("class C { void M(string s) { string local = """"; M([|local|]); } }", Nothing, Nothing)>
         <InlineData("class C { void M(string s) { M(s [|+|] s) }", Nothing, Nothing)>
         <InlineData("using [|S|] = System.String;", Nothing, Nothing)>
         <InlineData("class C { [|global|]::System.String s; }", "<global namespace>", WellKnownSymbolMonikerSchemes.DotnetNamespace)>
@@ -49,7 +49,9 @@ Namespace Microsoft.CodeAnalysis.LanguageServerIndexFormat.Generator.UnitTests
                             <Document Name="A.cs" FilePath="Z:\A.cs">
                                 <%= code %>
                             </Document>
+                            <ProjectReference Alias="A">ReferencedWithAlias</ProjectReference>
                         </Project>
+                        <Project AssemblyName="ReferencedWithAlias" Language="C#" FilePath="Z:\ReferencedWithAlias.csproj"></Project>
                     </Workspace>))
 
             Assert.Empty(lsif.Vertices.OfType(Of Range))

src/Features/Lsif/GeneratorTest/Utilities/TestLsifOutput.vb

@@ -30,6 +30,10 @@ Namespace Microsoft.CodeAnalysis.LanguageServerIndexFormat.Generator.UnitTests.U
 
             For Each project In workspace.CurrentSolution.Projects
                 Dim compilation = Await project.GetCompilationAsync()
+
+                ' Assert we don't have any errors to prevent any typos in the tests
+                Assert.Empty(compilation.GetDiagnostics().Where(Function(d) d.Severity = DiagnosticSeverity.Error))
+
                 generator.GenerateForCompilation(compilation, project.FilePath, project.LanguageServices)
             Next
         End Function