feat: make testing work again and improve coverage

[ashish10alex]

WARN:
If you have previously compiled this project via a debugger or manually using npm. Delete the out directory before running the test using npm run test as the previous compilation will have artefacts from the past tests and will result in failure of the new tests.

NOTE:
The test would not be able to run if your project path is very long this is a known issue reported in microsoft/vscode-test#232. Also, we are having to remove .vscode-test/user-data before running vscode-test in the npm run test script in package.json. These tests currently are only tested to be running on mac os. We will need to change the script for npm run test in package.json for it to work in multiple platforms

• Migrate to using vscode-test for testing
• Migrate previous tests

Add tests for getQueryMetaForCurrentFile function for

• Table
• Assertions
• Operation
• Incremental

Output of tests passing