Replaced Connection with GetClosedConnection in some unit tests… (#1337)

…cording to their names.

Dapper.Tests/AsyncTests.cs

@@ -18,12 +18,14 @@ public sealed class MicrosoftSqlClientAsyncTests : AsyncTests<MicrosoftSqlClient
 #endif
 
     [Collection(NonParallelDefinition.Name)]
-    public sealed class SystemSqlClientAsyncQueryCacheTests : AsyncQueryCacheTests<SystemSqlClientProvider> {
+    public sealed class SystemSqlClientAsyncQueryCacheTests : AsyncQueryCacheTests<SystemSqlClientProvider>
+    {
         public SystemSqlClientAsyncQueryCacheTests(ITestOutputHelper log) : base(log) { }
     }
 #if MSSQLCLIENT
     [Collection(NonParallelDefinition.Name)]
-    public sealed class MicrosoftSqlClientAsyncQueryCacheTests : AsyncQueryCacheTests<MicrosoftSqlClientProvider> {
+    public sealed class MicrosoftSqlClientAsyncQueryCacheTests : AsyncQueryCacheTests<MicrosoftSqlClientProvider>
+    {
         public MicrosoftSqlClientAsyncQueryCacheTests(ITestOutputHelper log) : base(log) { }
     }
 #endif
@@ -128,10 +130,13 @@ public void TestLongOperationWithCancellation()
         [Fact]
         public async Task TestBasicStringUsageClosedAsync()
         {
-            var query = await connection.QueryAsync<string>("select 'abc' as [Value] union all select @txt", new { txt = "def" }).ConfigureAwait(false);
+            using (var conn = GetClosedConnection())
+            {
+                var query = await conn.QueryAsync<string>("select 'abc' as [Value] union all select @txt", new { txt = "def" }).ConfigureAwait(false);
                 var arr = query.ToArray();
                 Assert.Equal(new[] { "abc", "def" }, arr);
             }
+        }
 
         [Fact]
         public async Task TestQueryDynamicAsync()
@@ -159,10 +164,13 @@ public async Task TestExecuteAsync()
         [Fact]
         public void TestExecuteClosedConnAsyncInner()
         {
-            var query = connection.ExecuteAsync("declare @foo table(id int not null); insert @foo values(@id);", new { id = 1 });
+            using (var conn = GetClosedConnection())
+            {
+                var query = conn.ExecuteAsync("declare @foo table(id int not null); insert @foo values(@id);", new { id = 1 });
                 var val = query.Result;
                 Assert.Equal(1, val);
             }
+        }
 
         [Fact]
         public async Task TestMultiMapWithSplitAsync()
@@ -248,17 +256,22 @@ public async Task TestMultiAsyncViaFirstOrDefault()
         [Fact]
         public async Task TestMultiClosedConnAsync()
         {
-            using (SqlMapper.GridReader multi = await connection.QueryMultipleAsync("select 1; select 2").ConfigureAwait(false))
+            using (var conn = GetClosedConnection())
+            {
+                using (SqlMapper.GridReader multi = await conn.QueryMultipleAsync("select 1; select 2").ConfigureAwait(false))
                 {
                     Assert.Equal(1, multi.ReadAsync<int>().Result.Single());
                     Assert.Equal(2, multi.ReadAsync<int>().Result.Single());
                 }
             }
+        }
 
         [Fact]
         public async Task TestMultiClosedConnAsyncViaFirstOrDefault()
         {
-            using (SqlMapper.GridReader multi = await connection.QueryMultipleAsync("select 1; select 2; select 3; select 4; select 5;").ConfigureAwait(false))
+            using (var conn = GetClosedConnection())
+            {
+                using (SqlMapper.GridReader multi = await conn.QueryMultipleAsync("select 1; select 2; select 3; select 4; select 5").ConfigureAwait(false))
                 {
                     Assert.Equal(1, multi.ReadFirstOrDefaultAsync<int>().Result);
                     Assert.Equal(2, multi.ReadAsync<int>().Result.Single());
@@ -267,6 +280,7 @@ public async Task TestMultiClosedConnAsyncViaFirstOrDefault()
                     Assert.Equal(5, multi.ReadFirstOrDefaultAsync<int>().Result);
                 }
             }
+        }
 
 #if !NETCOREAPP1_0
         [Fact]