Expose default database collation through 'sql-database-projects' extension API (#15538)

* Expose default database collation through 'sql-database-projects' extension API.

For the purpose of schema conversion we would need to know whether target database is configured as CI or CS. This will be used to produce a warning, if we detect a case-sensitive identifier, but database is configured as CI. In order to support this scenario we need to access `<DefaultCollation/>` property of the project.

This change adds new method to the `ISqlProject` interface that allows to read the value of the project property. There already was similar method for the SQL version/platform (`<DSP/>` property) and while working on the change, I took an opportunity to refactor the way project properties are extracted from the XML. Original code was hardcoded in the `getProjectTargetVersion` and I extracted it into separate `evaluateProjectPropertyValue` helper, that can be used in the future by any getter or access method that is supposed to return a value of the single property. This also allows us to improve the way properties are retrieved from the XML. Today the logic is very rudimentary - we read the first matching XML element with the required name. This is not correct as it does not verify the parent to be `<PropertyGroup/>`, neither it evaluates the `Condition` attributes nor property value itself. I did not invest in this, but added a TODO there explaining that the method may not perform as expected.

After the helper method was added, I updated the existing `getProjectTargetVersion` method to leverage it. The only complication here was the error throwing logic, as it was using custom error message. I preserved that, as there were tests verifying it already. For the new accessor method I did not introduce a special error message and rely on generic one I defined for use within the helper method. Additionally, for the collation we return default value of `SQL_Latin1_General_CP1_CI_AS`, if project does not have the property defined. This is what SSDT for Visual Studio shows in the UI when property is missing and I decided to align with that.

Finally, I added tests for both - original `getProjectTargetVersion` and new collation extraction method to make sure they work as expected. While working on the tests, I've noticed complaints that some rejected promises were not awaited. I added missing `await`s.

extensions/sql-database-projects/src/test/project.test.ts

@@ -233,11 +233,11 @@ describe('Project: sqlproj content operations', function (): void {
 		projFilePath = await testUtils.createTestSqlProjFile(baselines.newProjectFileBaseline);
 		const project = await Project.openProject(projFilePath);
 
-		should(project.databaseReferences.length).equal(0, 'There should be no datbase references to start with');
+		should(project.databaseReferences.length).equal(0, 'There should be no database references to start with');
 		await project.addSystemDatabaseReference({ databaseName: 'master', systemDb: SystemDatabase.master, suppressMissingDependenciesErrors: false });
 		should(project.databaseReferences.length).equal(1, 'There should be one database reference after adding a reference to master');
 		should(project.databaseReferences[0].databaseName).equal(constants.master, 'The database reference should be master');
-		should(project.databaseReferences[0].suppressMissingDependenciesErrors).equal(false, 'project.databaseReferences[1].suppressMissingDependenciesErrors should be false');
+		should(project.databaseReferences[0].suppressMissingDependenciesErrors).equal(false, 'project.databaseReferences[0].suppressMissingDependenciesErrors should be false');
 		// make sure reference to ADS master dacpac and SSDT master dacpac was added
 		let projFileText = (await fs.readFile(projFilePath)).toString();
 		should(projFileText).containEql(convertSlashesForSqlProj(project.getSystemDacpacUri(constants.master).fsPath.substring(1)));
@@ -754,6 +754,55 @@ describe('Project: add SQLCMD Variables', function (): void {
 	});
 });
 
+describe('Project: properties', function (): void {
+	before(async function (): Promise<void> {
+		await baselines.loadBaselines();
+	});
+
+	it('Should read target database version', async function (): Promise<void> {
+		projFilePath = await testUtils.createTestSqlProjFile(baselines.openProjectFileBaseline);
+		const project = await Project.openProject(projFilePath);
+
+		should(project.getProjectTargetVersion()).equal('150');
+	});
+
+	it('Should throw on missing target database version', async function (): Promise<void> {
+		projFilePath = await testUtils.createTestSqlProjFile(baselines.sqlProjectMissingVersionBaseline);
+		const project = await Project.openProject(projFilePath);
+
+		should(() => project.getProjectTargetVersion()).throw("Invalid DSP in .sqlproj file");
+	});
+
+	it('Should throw on invalid target database version', async function (): Promise<void> {
+		projFilePath = await testUtils.createTestSqlProjFile(baselines.sqlProjectInvalidVersionBaseline);
+		const project = await Project.openProject(projFilePath);
+
+		should(() => project.getProjectTargetVersion()).throw("Invalid DSP in .sqlproj file");
+	});
+
+	it('Should read default database collation', async function (): Promise<void> {
+		projFilePath = await testUtils.createTestSqlProjFile(baselines.sqlProjectCustomCollationBaseline);
+		const project = await Project.openProject(projFilePath);
+
+		should(project.getDatabaseDefaultCollation()).equal('SQL_Latin1_General_CP1255_CS_AS');
+	});
+
+	it('Should return default value when database collation is not specified', async function (): Promise<void> {
+		projFilePath = await testUtils.createTestSqlProjFile(baselines.newProjectFileBaseline);
+		const project = await Project.openProject(projFilePath);
+
+		should(project.getDatabaseDefaultCollation()).equal('SQL_Latin1_General_CP1_CI_AS');
+	});
+
+	it('Should throw on invalid default database collation', async function (): Promise<void> {
+		projFilePath = await testUtils.createTestSqlProjFile(baselines.sqlProjectInvalidCollationBaseline);
+		const project = await Project.openProject(projFilePath);
+
+		should(() => project.getDatabaseDefaultCollation())
+			.throw("Invalid value specified for the property 'DefaultCollation' in .sqlproj file");
+	});
+});
+
 describe('Project: round trip updates', function (): void {
 	before(async function (): Promise<void> {
 		await baselines.loadBaselines();