Add some basic docs. Remove pin for pytest; v4 should work ok

CONTRIBUTING.md

@@ -21,7 +21,8 @@ gdalinfo --version
 Run autotest suite:
 ```
 cd ../autotest
-python run_all.py
+pip install -r requirements.txt
+pytest
 ```
 
 Git workflows with GDAL

autotest/README.md

@@ -0,0 +1,56 @@
+# GDAL test suite
+
+
+## How to run tests
+
+1. You need to install `pytest` to run the test suite. This should do it:
+
+```bash
+cd autotest
+pip install -r ./requirements.txt
+```
+
+2. Then, run tests with:
+
+```bash
+pytest
+```
+
+3. Some quick usage tips:
+
+```bash
+# get more verbose output; don't capture stdout/stdin
+pytest -vvs
+
+# run all the gcore tests
+pytest gcore/
+
+# run a particular module only
+pytest gcore/basic_test.py
+```
+
+
+## GDAL's tests are not independent
+
+GDAL's test functions are not currently independent of each other. In particular, running individual test functions from a given module may not work. Most tests were originally written with the assumption that entire modules will be run at once.
+
+Practically, this means that you should avoid using:
+
+
+* pytest's `--last-failed` / `--lf` option (since it runs only failed tests, not the whole module)
+* test specifiers that run individual tests (e.g. `pytest gcore/basic_test.py::test_basic_test_1` )
+* the xunit plugin to run tests in parallel, unless you also use `--dist=loadfile`. (This may have other issues; untested)
+
+This will hopefully be addressed in the future. When writing new tests, please try to make them independent of each other.
+
+
+## Notes about availability of GDAL sample and test data
+
+The GDAL Team makes every effort to assure that all sample data files
+available from GDAL download server (http://download.osgeo.org/gdal/data/) and
+test data files used in GDAL Autotest package (https://github.com/OSGeo/gdal/tree/master/autotest)
+are available as public and freely redistributable geodata.
+
+--
+
+http://gdal.org/

autotest/requirements.txt

@@ -1,2 +1,2 @@
-pytest>=3,<3.10
+pytest>=3
 pytest-sugar

gdal/scripts/vagrant/gdal.sh

@@ -71,3 +71,13 @@ make generate
 make
 make vagrant_safe_test
 cd ../..
+
+# Install pytest.
+# First install pip 9, which is the last version which can upgrade the system's `six`
+# 10+ throws an error :/
+curl https://bootstrap.pypa.io/get-pip.py 'pip<10' | sudo -H python
+
+sudo -H pip install -Ur /vagrant/autotest/requirements.txt
+
+# Add python symbols so gdb is friendlier
+sudo apt-get install -y python2.7-dbg