How to create a negative test case in GitHub - testing

Question

I am working on a repository in GitHub and learning to use their Workflows and Actions to execute CI tests. I have created a simple workflow that runs against a shell script to test a simple mathematical expression y-x=expected_val. This workflow isn't that different from other automatic tests I have set up on code in the past, but I cannot figure out how to perform negative test cases.
on:
push:
branches:
- 'Math-Test-Pass*'
jobs:
build:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout#v1
- name: T1. Successful math test
uses: ./.github/actions/mathTest
with:
OPERAND1: 3
OPERAND2: 5
ANSWER: 2
- name: T2. Mismatch answer math test
if: ${{ always() }}
uses: ./.github/actions/mathTest
with:
OPERAND1: -3
OPERAND2: 2
ANSWER: 1
- name: T3. Missing operand math test
if: ${{ always() }}
uses: ./.github/actions/mathTest
with:
OPERAND1: -3
ANSWER: 5
- name: T4. Another test should pass
if: ${{ always() }}
uses: ./.github/actions/mathTest
with:
OPERAND1: 6
OPERAND2: 9
ANSWER: 3
- name: T5. Another test should pass
uses: ./.github/actions/mathTest
with:
OPERAND1: 1
OPERAND2: 9
ANSWER: 8
Now, I expected tests T.2 and T.3 to fail, but I run into two problems. First, I want all the steps to execute and the errors thrown by T.2 and T.3 make the job status a failure. Github's default response is to not run any additional steps unless I force it with something like if: ${{ always() }} This means that T.3 and T.4 only run because of that logic and T.5 doesn't run at all. See below.
The second problem is that while the mathTest action failed on T.2 and T.3 that was the intended behavior. It did exactly what it was supposed to do by failing. I wanted to show that by improperly configuring the parameters the script would fail. These negative pass tests shouldn't show up as failures, but as successes. The whole math test should pass to show that the script in question was prompting the right errors as well as the right answers.
There is a third case that doesn't show here. I definitely don't want to use continue on error. If the script failed to throw an error I want the test case to fail. There should be a failure and then the rest of the tests should continue. My ideal solution would show a pass on T.2 and T.3 and run T.4 and T.5. The same solution would also fail on T.2 or T.3 if they didn't generate an exception and still run T.4 and T.5. I just don't know how to fix that.
I have considered a couple of options but I don't know what is usually done. I expect that while I could jury rig something (e.g. put the failure into the script as another parameter, nest the testing in a second script that passes the parameters and catches the error, etc.), there is some standard way of doing this that I haven't considered. I'm looking for anyone who can tell me how it should be done.

Answer 1

I obtained an answer from the GitHub community that I want to share here.
https://github.community/t/negative-testing-with-workflows/116559
The answer is that the workflow should kick off one of several tools instead of multiple actions and that the tools can handle positive/negative testing on their own. The example given by the respondent is https://github.com/lee-dohm/close-matching-issues/blob/c65bd332c8d7b63cc77e463d0103eed2ad6497d2/.github/workflows/test.yaml#L16 which uses npm for testing.