C#: Update unit tests.

Author: michaelnebel

csharp/extractor/Semmle.Extraction.Tests/Options.cs

@@ -22,7 +22,7 @@ public void DefaultOptions()
         {
             options = CSharp.Options.CreateWithEnvironment(Array.Empty<string>());
             Assert.True(options.Cache);
-            Assert.False(options.CIL);
+            Assert.True(options.CIL);
             Assert.Null(options.Framework);
             Assert.Null(options.CompilerName);
             Assert.Empty(options.CompilerArguments);
@@ -51,10 +51,20 @@ public void Cache()
         [Fact]
         public void CIL()
         {
-            options = CSharp.Options.CreateWithEnvironment(new string[] { "--cil" });
+            options = CSharp.Options.CreateWithEnvironment(Array.Empty<string>());
             Assert.True(options.CIL);
-            options = CSharp.Options.CreateWithEnvironment(new string[] { "--cil", "--nocil" });
+
+            Environment.SetEnvironmentVariable("CODEQL_EXTRACTOR_CSHARP_OPTION_CIL", "false");
+            options = CSharp.Options.CreateWithEnvironment(Array.Empty<string>());
             Assert.False(options.CIL);
+
+            Environment.SetEnvironmentVariable("CODEQL_EXTRACTOR_CSHARP_OPTION_CIL", "true");
+            options = CSharp.Options.CreateWithEnvironment(Array.Empty<string>());
+            Assert.True(options.CIL);
+
+            Environment.SetEnvironmentVariable("CODEQL_EXTRACTOR_CSHARP_OPTION_CIL", null);
+            options = CSharp.Options.CreateWithEnvironment(Array.Empty<string>());
+            Assert.True(options.CIL);
         }
 
         [Fact]
@@ -121,22 +131,6 @@ public void Framework()
             Assert.Equal("foo", options.Framework);
         }
 
-        [Fact]
-        public void EnvironmentVariables()
-        {
-            Environment.SetEnvironmentVariable("LGTM_INDEX_EXTRACTOR", "--cil c");
-            options = CSharp.Options.CreateWithEnvironment(new string[] { "a", "b" });
-            Assert.True(options.CIL);
-            Assert.Equal("a", options.CompilerArguments[0]);
-            Assert.Equal("b", options.CompilerArguments[1]);
-            Assert.Equal("c", options.CompilerArguments[2]);
-
-            Environment.SetEnvironmentVariable("LGTM_INDEX_EXTRACTOR", "");
-            Environment.SetEnvironmentVariable("LGTM_INDEX_EXTRACTOR", "--nocil");
-            options = CSharp.Options.CreateWithEnvironment(new string[] { "--cil" });
-            Assert.False(options.CIL);
-        }
-
         [Fact]
         public void StandaloneDefaults()
         {