test(robot-server): Deduplicate and tidy up integration test fixtures

[SyntaxColoring]

Overview

Some Friday zen refactoring because I needed something easy and gratifying. This tidies up robot-server's integration test infrastructure.

Notable changes

Less URL construction

Integration tests no longer have to repeat the {host:s}:{port:d} thing for every request. They can now use {ot2_server_base_url} or {ot3_server_base_url}.

Less error-prone test isolation

Before this PR, each integration test had to remember to use clean_server_state to reset the shared dev server. Otherwise, the runs and protocols that it added would leak into subsequent tests.

Writing the tests this way was a deliberate choice in #12193 for explicitness, but I think it was turning out to be too easy to forget, especially with how much copy-pasting we do in Tavern files.

With this PR, that cleanup is now built in to the dev server fixture itself. This gives us test isolation by default, which is what we normally expect in pytest.

Less duplication

This resolves a bit of duplication that had grown over time. A lot of this was my fault, like #12595 (comment).

Review requests

You definitely do not have to review all 60+ files. The vast majority of the changes are simple renames. Here are the most meaningful files:

• robot-server/tests/integration/conftest.py
• robot-server/tests/integration/common.yaml
• robot-server/tests/integration/fixtures.py
• robot-server/tests/integration/http_api/protocols/test_upload_robot_type_rejection.tavern.yaml, as an example of how most of the other Tavern files change

Test plan

Make sure CI keeps passing.

Risk assessment

Low. Changes are only to tests.

[codecov]

Codecov Report

Merging #12795 (6bbfeba) into edge (c9a7fa0) will decrease coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             edge   #12795      +/-   ##
==========================================
- Coverage   73.50%   73.49%   -0.01%     
==========================================
  Files        2261     2271      +10     
  Lines       62047    62159     +112     
  Branches     6717     6736      +19     
==========================================
+ Hits        45605    45684      +79     
- Misses      14842    14867      +25     
- Partials     1600     1608       +8     

Flag	Coverage Δ
app	71.49% <ø> (ø)
components	67.87% <ø> (+0.71%)	⬆️
labware-library	49.74% <ø> (ø)
protocol-designer	46.35% <ø> (ø)
react-api-client	71.03% <ø> (-3.37%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

see 27 files with indirect coverage changes

[sfoster1]

Looks like the right call to me. Explicit is good but in addition to the copy pasting issue, forgetting the clean fixture would lead to nonlocal failures which are awful to debug. I think the downsides outweigh the upsides.