What Is the task? And the description of the task

Task: As a developer, I need a reusable templating class that can be used to enable a variety of templating needs

Description:

• Create and contribute a Template Class that matches that outlined in the Template Tool Design Doc

• A Template class scaffolding has been included here. All methods and functionality should be filled in

• The work of hooking this Template Class into the existing Namelist Handler Tool will be done as part of UW-192

• The templater.py currently does a lot of this work, but in its "main" function

• Tests for this Class and its methods can be written and committed in tests/test_template.py

What does this mean?

From a quick read of the description I had several follow-up questions:

• What does It mean by a reusable template?

• It seems as though we'll be editing the Template class scaffolding provided to us. Are there any example files we can model our file off of?

• What is the difference between this new Template class and what templater.py does currently?

• Does this ticket consist of writing the Template Class and Unit Tests for the class?

Accomplishing the Task

For ticket 191 there were a lot of resources that needed to be sifted through before addressing the task. This Involved going through template.py, which currently did a lot of this work and understanding why we were shifting away from this code. Accomplishing UW-191 became a bigger task than we previously Imagined. We first needed to understand UW-191 and set-up the project.

Emily and I found a recurring theme from Sprint 6.2, where we would be In a meeting and feel like we understood the vision and the Inner workings of 191 much more clearer, but when we went to pair program on It we couldn't make much progress. Due to this we set-up an additional Tagup meeting with Christina for Monday before our weekly Tuesday Tagup. In this extra meeting we were able to gain more clarity around what the test cases should look like. Christina was able to provide us with sample code that hopefully would get us over that last hurdle In understanding 191.

Sample Code:

Hi there {{ name }}

J2Template(template_str="Hi there {{name}}")

J2Template(template_path="/path/to/test/file")

test_config = {'name': 'Christina'}

mytemplate = J2Template(test_config, template_str="Hi there {{name}}")

assert "Hi there Christina" == mytemplate.render_template()

With less than one week left In the sprint and no code to show for our efforts I think we both began to feel discouraged. We decided before our normally scheduled tagup meeting we would try to write some example test cases to get feedback from Christina to see If we were going In the right direction. Within j2template.py we had seven functions:

1. __init__(self, configure_obj, template_path=None, template_str=None)

2. dump_file(self, output_path)

3. _load_file(self, template_path)

4. _load_string(self, template_str)

5. render_template(self)

6. undeclared_variables(self)

7. validate_config(self)

Starting with dump_file, _load_file, and _load_string was the easiest for us because they were the simplest functions and had the least amount of parameters. A parameter Is 'a variable in a function definition, It is a placeholder and hence does not have a concrete value.' For example, self, output_path and template_str are all parameters within the function definitions listed above. After writing a couple basic test cases we were able to run them locally, but were getting too many errors to narrow down the problem. We decided to wait for our weekly tagup to get feedback from Christina.

Showing Christina our test cases, she was able to point us In the right direction. Once you close out of a terminal window on your local computer, you have to reactivate your conda environment using the line 'conda activate <environment>', our environment was set to 'wf_tools_test,' however we had not reactivated our environment In the terminal. Following the reactivation of the environment, we were able to see that 1/3 of our test cases passed. We were also given more helpful errors output by the terminal to debug the other two test cases, and within 10 mins had three working test cases(Images 5 - 7 highlight some of the errors we saw). Reviewing our tests we had already tested the __Init__ and render_template functions as well. This meant that If we could test undeclared_variables and validate_config we would have accomplished UW-191.

Feedback:

Gaining some more Information from Christina, she asked us to remove the code for validate_config completely from j2template.py, allowing us to skip a test case for this function. We also were informed that passing the pytests In the command line weren't the only test we needed to run, we also needed to pass the pylint tests for uwtools and tests.

What is Pylint? Pylint doesn't run your code, but checks it and enforces a coding standard. 'It can tell you the issues in your program and also, a way to resolve them, ultimately giving you feedback on your code.' Essentially, Pylint would confirm the code we wrote In j2template.py and test_template.py was up to PEP-8 standards.

With that knowledge, we began working on testing undeclared_vairables and running both sets of test cases - pytest and pylint.