Use preferred Assert.* patterns

Visual Studio pointed out a couple of instances where `Assert.Equal(0,
X.Count)` was used instead of `Assert.Empty(X)`, and similarly
`Assert.Equal(1, X.Count)` instead of `Assert.Single(X)`.

Let's accept the suggested fixes and thereby address the last remaining
warnings when building in Visual Studio.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

src/shared/Core.Tests/ApplicationTests.cs

@@ -244,7 +244,7 @@ public async Task Application_UnconfigureAsync_EmptyAndGcmWithOthersBefore_Remov
 
             Assert.Single(context.Git.Configuration.Global);
             Assert.True(context.Git.Configuration.Global.TryGetValue(key, out var actualValues));
-            Assert.Equal(1, actualValues.Count);
+            Assert.Single(actualValues);
             Assert.Equal(beforeHelper, actualValues[0]);
         }
 

src/shared/Core.Tests/CurlCookieTests.cs

@@ -37,7 +37,7 @@ public void CurlCookieParser_Parse_MissingFields_SkipsInvalidLines()
 
         IList<Cookie> actual = parser.Parse(content);
 
-        Assert.Equal(1, actual.Count);
+        Assert.Single(actual);
         AssertCookie(actual[0], ".example.com", "/path/here", true, 0, "cookie1", "value1");
     }
 

src/shared/Core.Tests/HostProviderRegistryTests.cs

@@ -119,7 +119,7 @@ public async Task HostProviderRegistry_GetProvider_Auto_HasProviders_DynamicMatc
 
             Assert.Same(providerMock.Object, result);
             Assert.True(context.Git.Configuration.Global.TryGetValue(configKey, out IList<string> config));
-            Assert.Equal(1, config.Count);
+            Assert.Single(config);
             Assert.Equal(providerId, config[0]);
         }
 
@@ -148,7 +148,7 @@ public async Task HostProviderRegistry_GetProvider_Auto_HasProviders_DynamicMatc
 
             Assert.Same(providerMock.Object, result);
             Assert.True(context.Git.Configuration.Global.TryGetValue(configKey, out IList<string> config));
-            Assert.Equal(1, config.Count);
+            Assert.Single(config);
             Assert.Equal(providerId, config[0]);
         }
 

src/shared/Core.Tests/IniFileTests.cs

@@ -79,7 +79,7 @@ recovery tests]
             Assert.Equal(6, ini.Sections.Count);
 
             AssertSection(ini, "one", out IniSection one);
-            Assert.Equal(1, one.Properties.Count);
+            Assert.Single(one.Properties);
             AssertProperty(one, "foo", "123");
 
             AssertSection(ini, "two", out IniSection twoA);
@@ -88,7 +88,7 @@ recovery tests]
             AssertProperty(twoA, "widget", "Hello, World!");
 
             AssertSection(ini, "two", "subsection name", out IniSection twoB);
-            Assert.Equal(1, twoB.Properties.Count);
+            Assert.Single(twoB.Properties);
             AssertProperty(twoB, "foo", "this is different");
 
             AssertSection(ini, "three", out IniSection three);
@@ -97,7 +97,7 @@ recovery tests]
             AssertProperty(three, "empty", "");
 
             AssertSection(ini, "four", out IniSection four);
-            Assert.Equal(0, four.Properties.Count);
+            Assert.Empty(four.Properties);
 
             AssertSection(ini, "five", out IniSection five);
             Assert.Equal(3, five.Properties.Count);

src/shared/Core.Tests/StreamExtensionsTests.cs

@@ -21,7 +21,7 @@ public void StreamExtensions_ReadDictionary_EmptyString_ReturnsEmptyDictionary()
             var output = ReadStringStream(input, StreamExtensions.ReadDictionary);
 
             Assert.NotNull(output);
-            Assert.Equal(0, output.Count);
+            Assert.Empty(output);
         }
 
         [Fact]
@@ -73,7 +73,7 @@ public void StreamExtensions_ReadDictionary_CaseInsensitive_ReturnsDictionaryWit
             var output = ReadStringStream(input, x => StreamExtensions.ReadDictionary(x, StringComparer.OrdinalIgnoreCase));
 
             Assert.NotNull(output);
-            Assert.Equal(1, output.Count);
+            Assert.Single(output);
             AssertDictionary("2", "a", output);
         }
 
@@ -197,7 +197,7 @@ public void StreamExtensions_ReadMultiDictionary_EmptyString_ReturnsEmptyDiction
             var output = ReadStringStream(input, StreamExtensions.ReadMultiDictionary);
 
             Assert.NotNull(output);
-            Assert.Equal(0, output.Count);
+            Assert.Empty(output);
         }
 
         [Fact]
@@ -250,7 +250,7 @@ public void StreamExtensions_ReadMultiDictionary_CaseInsensitive_ReturnsDictiona
             var output = ReadStringStream(input, x => StreamExtensions.ReadMultiDictionary(x, StringComparer.OrdinalIgnoreCase));
 
             Assert.NotNull(output);
-            Assert.Equal(1, output.Count);
+            Assert.Single(output);
             AssertMultiDictionary(new[] { "2" }, "a", output);
         }
 
@@ -262,7 +262,7 @@ public void StreamExtensions_ReadMultiDictionary_EmptyString_ReturnsKeyWithEmpty
             var output = ReadStringStream(input, StreamExtensions.ReadMultiDictionary);
 
             Assert.NotNull(output);
-            Assert.Equal(1, output.Count);
+            Assert.Single(output);
 
             AssertMultiDictionary(new[] { String.Empty,  }, "a", output);
         }

src/shared/TestInfrastructure/Objects/TestHttpMessageHandler.cs

@@ -65,7 +65,7 @@ public void AssertRequest(HttpMethod method, Uri uri, int expectedNumberOfCalls)
 
         public void AssertNoRequests()
         {
-            Assert.Equal(0, _requestCounts.Count);
+            Assert.Empty(_requestCounts);
         }
 
         #region HttpMessageHandler