Warning for multiple delete (#931)

* Fix for multiple delete bug

* minor space removal

* removed catch error in RowDelete

* small optimizations

* space adding

* WIP on creating test

* Some cleanup

* removed spaces

* Fix for verifytext

* Added check for command format correctness.

* tidying up

* added working test for command exception

* simplification of TestDbDataReader getint

* Corrections made

* spacing and naming issues

* minor space

* one more space issue

test/Microsoft.SqlTools.ServiceLayer.UnitTests/EditData/RowDeleteTests.cs

@@ -193,6 +193,56 @@ namespace Microsoft.SqlTools.ServiceLayer.UnitTests.EditData
             Assert.Throws<InvalidOperationException>(() => rd.RevertCell(0));
         }
 
+        [Fact]
+        public async Task GetVerifyQuery()
+        {
+            // Setup: Create a row update and set the first row cell to have values
+            // ... other than "1" for testing purposes (simulated select query result).
+            Common.TestDbColumnsWithTableMetadata data = new Common.TestDbColumnsWithTableMetadata(false, false, 0, 0);
+            var rs = await Common.GetResultSet(data.DbColumns, false);
+            RowUpdate ru = new RowUpdate(0, rs, data.TableMetadata);
+            object[][] rows =
+            {
+                new object[] {"2", "0", "0"},
+            };
+            var testResultSet = new TestResultSet(data.DbColumns, rows);
+            var newRowReader = new TestDbDataReader(new[] { testResultSet }, false);
+            await ru.ApplyChanges(newRowReader);
+
+            // ... Create a row delete.
+            RowDelete rd = new RowDelete(0, rs, data.TableMetadata);
+            int expectedKeys = 3;
+
+            // If: I generate a verify command
+            String verifyCommand = rd.GetVerifyScript();
+
+            // Then:
+            // ... The command should not be null
+            Assert.NotNull(verifyCommand);
+
+            // ... It should be formatted into an where script
+            string regexTest = @"SELECT COUNT \(\*\) FROM (.+) WHERE (.+)";
+            Regex r = new Regex(regexTest);
+            var m = r.Match(verifyCommand);
+            Assert.True(m.Success);
+
+            // ... There should be a table
+            string tbl = m.Groups[1].Value;
+            Assert.Equal(data.TableMetadata.EscapedMultipartName, tbl);
+
+            // ... There should be as many where components as there are keys
+            string[] whereComponents = m.Groups[2].Value.Split(new[] { "AND" }, StringSplitOptions.None);
+            Assert.Equal(expectedKeys, whereComponents.Length);
+
+            // ... Mock db connection for building the command
+            var mockConn = new TestSqlConnection(new[] { testResultSet });
+
+            // If: I attempt to get a command for a simulated delete of a row with duplicates.
+            // Then: The Command will throw an exception as it detects there are
+            // ... 2 or more rows with the same value in the simulated query results data.
+            Assert.Throws<EditDataDeleteException>(() => rd.GetCommand(mockConn));
+        }
+
         private async Task<RowDelete> GetStandardRowDelete()
         {
             Common.TestDbColumnsWithTableMetadata data = new Common.TestDbColumnsWithTableMetadata(false, false, 0, 0);