Peek definition support for tables, views and stored procedures (#160)

* Add support for peek/go to definition
Add unit tests for definition

Microsoft/vscode-mssql#253 and Microsoft/vscode-mssql#268

* Format Strings

* Add integration tests

* Refactor variable names

* Remove test file

* Remove LIVE_CONNECTION definition

* Change method name

* Write files to a separate directory

* Refactor GetDefinition

* Remove unnecessary whitespace and modify variable name

* Check intellisense settings

* Refactor code to be scalable and modify tests

* Refactor to facilitate CodeGen

* Reorder methods

* Modify method to strip bracket syntax

* Add one_second constant

* Add comments

* Modify null check

* Modify GetSchema code to account for spaces

* Alter variable names and modify null checks

* Remove timeout callback and refactor null check

* remove LIVE_CONNECTION_TEST definition

test/Microsoft.SqlTools.ServiceLayer.TestDriver/Tests/LanguageServiceTests.cs

@@ -211,6 +211,49 @@ namespace Microsoft.SqlTools.ServiceLayer.TestDriver.Tests
             }
         }
 
+        /// <summary>
+        /// Peek Definition/ Go to definition 
+        /// </summary>
+        /// <returns></returns>
+        [Fact]
+        public async Task DefinitionTest()
+        {
+            using (SelfCleaningTempFile queryTempFile = new SelfCleaningTempFile())
+            using (TestHelper testHelper = new TestHelper())
+            {
+                string query = "SELECT * FROM sys.objects";
+                int lineNumber = 0;
+                int position = 23;
+
+                testHelper.WriteToFile(queryTempFile.FilePath, query);
+
+                DidOpenTextDocumentNotification openParams = new DidOpenTextDocumentNotification
+                {
+                    TextDocument = new TextDocumentItem
+                    {
+                        Uri = queryTempFile.FilePath,
+                        LanguageId = "enu",
+                        Version = 1,
+                        Text = query
+                    }
+                };
+
+                await testHelper.RequestOpenDocumentNotification(openParams);
+                  
+                Thread.Sleep(500);
+
+                bool connected = await testHelper.Connect(queryTempFile.FilePath, ConnectionTestUtils.LocalhostConnection);
+                Assert.True(connected, "Connection is successful");
+
+                Thread.Sleep(10000);
+                // Request definition for "objects"
+                Location[] locations = await testHelper.RequestDefinition(queryTempFile.FilePath, query, lineNumber, position);
+                
+                Assert.True(locations != null, "Location is not null and not empty");
+                await testHelper.Disconnect(queryTempFile.FilePath);
+            }
+        }
+
         /// <summary>
         /// Validate the configuration change event
         /// </summary>

test/Microsoft.SqlTools.ServiceLayer.TestDriver/Tests/TestHelper.cs

@@ -257,6 +257,29 @@ namespace Microsoft.SqlTools.ServiceLayer.TestDriver.Tests
             return result;
         }
 
+        /// <summary>
+        /// Request definition( peek definition/go to definition) for a sql object in a sql string
+        /// </summary>
+        public async Task<Location[]> RequestDefinition(string ownerUri, string text, int line, int character)
+        {
+            // Write the text to a backing file
+            lock (fileLock)
+            {
+                System.IO.File.WriteAllText(ownerUri, text);
+            }
+
+            var definitionParams = new TextDocumentPosition();
+            definitionParams.TextDocument = new TextDocumentIdentifier();
+            definitionParams.TextDocument.Uri = ownerUri;
+            definitionParams.Position = new Position();
+            definitionParams.Position.Line = line;
+            definitionParams.Position.Character = character;
+
+            // Send definition request
+            var result = await Driver.SendRequest(DefinitionRequest.Type, definitionParams);
+            return result;
+        }
+
         /// <summary>
         /// Run a query using a given connection bound to a URI
         /// </summary>