Make (Install from Source) Python Without Running Tests

Make (install from source) python without running tests

The configure option --enable-optimizations enables running test suites to generate data for profiling Python. The resulting python binary has better performance in executing python code. Improvements noted here

From configure help:
--enable-optimizations  Enable expensive optimizations (PGO, etc). Disabled by default.

From wikipedia

 profile-guided optimisation uses the results of profiling test runs of the instrumented program to optimize the final generated code.

In short, you should not skip tests when using --enable-optimizations as the data required for profiling is generated by running tests.
You can run make -j8 build_all followed by make -j8 install to skip tests once(the tests would still run with install target), but that would defeat the purpose.
You can instead drop the configure flag for better build times.

Build python from source without creating symlink for binary

make altinstall is made exactly for that:

make install can overwrite or masquerade the python3 binary. make altinstall is therefore recommended instead of make install since it
only installs exec_prefix/bin/pythonversion.

How to run tests without installing package?

I know this question has been already closed, but a simple way I often use is to call pytest via python -m, from the root (the parent of the package).

$ python -m pytest tests

This works because -m option adds the current directory to the python path, and hence mypkg is detected as a local package (not as the installed).

See:
https://docs.pytest.org/en/latest/usage.html#calling-pytest-through-python-m-pytest

building Python from source with zlib support

The solution is to install the Ubuntu package dpkg-dev.

sudo apt-get install dpkg-dev

The reason is explained here.

In short, recent versions of Ubuntu don't store libz.so in the standard /usr/lib location, but rather in a platform specific location. For example, on my system is is in /usr/lib/x86_64-linux-gnu. This prevents Python's build system from finding it.

The dpkg-dev package installs the dpkg-architecture executable, which enables Python to find the necessary libraries.

The original question was about Python 3.2.3. I also downloaded Python 2.7.3 and confirmed that the same problem exists, and this solution is applicable to it as well.

Does it make sense to install my Python unit tests in site-packages?

After researching this issue, and until someone more experienced has a minute to weigh in to the contrary, my understanding is that the simple answer is: "No, unit tests should not be installed, only included in the source distribution".

In the handful of cases I found where tests were installed, all turned out to be accidental and it's easier than one might think to make the mistake without noticing it.

Here's how it happens:

1. The packages=find_packages() parameter is used in setup.py so packages can be found without having to list them out explicitly.
2. The test folder is made into a package (by adding __init__.py) so tests can reference the modules they test using relative naming (like from .. import pkg.mod).
3. setuptools installs test as a separate package, alongside the other(s) in the project. Note this means you can execute import test in the python interpreter and it works, almost certainly not what you intended, especially since a lot of other folks use that name for their test directory :)

The fix is to use the setting: packages=find_packages(exclude=['test']) to prevent your test directory from being installed.

Install python on Linux from source with custom paths

The process is quite straight forward, let's say you want to install in your $HOME

# 0) Download python source and extracted it to $HOME/tmp/Python3.9.2 directory
# 1)
mkdir $HOME/usr
# 2)
cd $HOME/tmp/Python3.9.2
# 3)
./configure --prefix=$HOME/usr && make
# 4) Now python is built in $HOME/tmp/Python3.9.2, give it a test, then
make install
# Now you should have $HOME/usr/bin/python ready to use.

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