Fix/changes current working dir when using a dbt project dir

[rariyama]

resolves #8997
I closed the previous PR by mistake, then I submit this one.

Problem

There is a difference in behaviour between dbt cli and dbt.invoke.
For example, When executing dbtRunner().invoke(["deps", "--project-dir", "project_dir"]) in python, directory
changes to project_dir, even though it doesn't affect when executing dbt deps.

Solution

The reason why directory changes is dbt.task.base.move_to_nearest_project_dir() is called in CleanTask , DepsTask and InitTask . Directory changes to the argument of the function.
It'll be possible to resolve this problem by using those classes as a context manager. The change will happen only in with statement.

Checklist

• I have read the contributing guide and understand what's expected of me
• I have run this code in development and it appears to resolve the stated issue
• This PR includes tests, or tests are not required/relevant for this PR
• This PR has no interface changes (e.g. macros, cli, logs, json artifacts, config files, adapter interface, etc) or this PR has already received feedback and approval from Product or DX
• This PR includes type annotations for new and modified functions

[ChenyuLInx]

Thanks for adding this @rariyama
I wonder what if you can add the __enter__ and __exit__ to just the base task so we only do it once?

Also tagging @MichelleArk to see if there are any thoughts on starting this with pattern. It looks good to me.

[rariyama]

Hi @ChenyuLInx . Thanks for your comments.
I agree with your idea, then I updated my code as follows on this commit 31ba979.

• Added __enter__ and __exit__ to BaseTask
• each child TaskClass inherits that class and behaves as a context manager.

I would like to add test code for this update. I feel like it's good enough to add the following code to integration test but what do you think about?

    def test_dbtRunner_invoke(self):
        pd = "<test-project-path>"
        dr = dbtRunner()
        commands = ["deps", "clean", "init"]

        for command in commands:
            req = [command, "--project-dir", pd, "--profiles-dir", pd]
            before_dir = os.getcwd()
            res = dr.invoke(req)
            self.assertEqual(res.success, True)
            # MEMO: Test whether directory is not changed after command is invoked.

            self.assertEqual(before_dir, os.getcwd())