add integration test

[frostming]

Pull Request Check List

• A news fragment is added in news/ describing what is new.
• Test cases added for changed code.

Describe what you have changed in this PR.

[sourcery-ai]

Sourcery Code Quality Report

✅  Merging this PR will increase code quality in the affected files by 0.05%.

Quality metrics	Before	After	Change
Complexity	1.69 ⭐	1.69 ⭐	0.00
Method Length	43.06 ⭐	42.74 ⭐	-0.32 👍
Working memory	9.60 🙂	9.60 🙂	0.00
Quality	75.43% ⭐	75.48% ⭐	0.05% 👍

Other metrics	Before	After	Change
Lines	366	366	0

Changed files	Quality Before	Quality After	Quality Change
pdm/pep508.py	71.43% 🙂	71.95% 🙂	0.52% 👍
pdm/installers/_editable_install.py	63.95% 🙂	63.95% 🙂	0.00%
pdm/models/builders.py	76.14% ⭐	76.14% ⭐	0.00%
pdm/models/in_process.py	81.35% ⭐	81.35% ⭐	0.00%

Here are some functions in these files that still need a tune-up:

File	Function	Complexity	Length	Working Memory	Quality	Recommendation
pdm/pep508.py	default_environment	2 ⭐	72 🙂	27 ⛔	56.06% 🙂	Extract out complex expressions
pdm/installers/_editable_install.py	install	1 ⭐	89 🙂	18 ⛔	58.69% 🙂	Extract out complex expressions
pdm/models/builders.py	EnvBuilder.__init__	4 ⭐	123 😞	9 🙂	64.09% 🙂	Try splitting into smaller methods
pdm/models/builders.py	EnvBuilder._get_pip_command	6 ⭐	92 🙂	10 😞	64.18% 🙂	Extract out complex expressions
pdm/models/builders.py	EnvBuilder._get_pip_command.__enter__	1 ⭐	70 🙂	14 😞	65.74% 🙂	Extract out complex expressions

Legend and Explanation

The emojis denote the absolute quality of the code:

• ⭐ excellent
• 🙂 good
• 😞 poor
• ⛔ very poor

The 👍 and 👎 indicate whether the quality has improved or gotten worse with this pull request.

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Please see our documentation here for details on how these metrics are calculated.

We are actively working on this report - lots more documentation and extra metrics to come!

Let us know what you think of it by mentioning @sourcery-ai in a comment.

[codecov-io]

Codecov Report

Merging #377 (9edefc3) into master (8e35c02) will increase coverage by 0.32%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master     #377      +/-   ##
==========================================
+ Coverage   82.38%   82.71%   +0.32%     
==========================================
  Files          63       63              
  Lines        5183     5183              
  Branches      933      933              
==========================================
+ Hits         4270     4287      +17     
+ Misses        638      625      -13     
+ Partials      275      271       -4     

Flag	Coverage Δ
unittests	82.65% <66.66%> (+0.34%)	⬆️

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

Impacted Files	Coverage Δ
pdm/models/builders.py	81.52% <50.00%> (ø)
pdm/models/in_process.py	88.00% <100.00%> (ø)
pdm/models/readers.py	48.47% <0.00%> (-1.75%)	⬇️
pdm/models/environment.py	85.71% <0.00%> (+0.47%)	⬆️
pdm/cli/utils.py	81.34% <0.00%> (+0.79%)	⬆️
pdm/formats/requirements.py	87.09% <0.00%> (+1.07%)	⬆️
pdm/models/pip_shims.py	83.75% <0.00%> (+2.50%)	⬆️
pdm/utils.py	71.32% <0.00%> (+3.67%)	⬆️
pdm/models/caches.py	71.64% <0.00%> (+5.97%)	⬆️
pdm/formats/setup_py.py	100.00% <0.00%> (+9.09%)	⬆️

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