Add --driver option to test suite for selecting minizinc executable

tests/README.md

@@ -24,6 +24,11 @@ Use the `--solvers` option to specify a subset of solvers to use in the tests. T
 pytest --solvers gecode,chuffed
 ```
 
+Use the `--driver` option to specify the directory containing the minizinc executable. Otherwise, default directories and PATH will be used to locate it.
+```sh
+pytest --driver=../build
+```
+
 ## Multiple test suites
 
 To facilitate running the test suite with different minizinc options, `specs/suites.yml` contains configurations for running tests, or a subset of tests using different options.

tests/conftest.py

@@ -13,8 +13,15 @@
 import sys
 
 
-def pytest_configure():
+def pytest_configure(config):
     pytest.solver_cache = {}
+    search = config.getoption("--driver")
+    if search is not None:
+        driver = mzn.find_driver([search])
+        if driver is None:
+            raise Exception("Failed to find MiniZinc driver in {}".format(search))
+        driver.make_default()
+
 
 def pytest_addoption(parser):
     parser.addoption(
@@ -33,6 +40,12 @@ def pytest_addoption(parser):
     parser.addoption(
         "--all-suites", action="store_true", dest="feature", help="Run all test suites"
     )
+    parser.addoption(
+        "--driver",
+        action="store",
+        metavar="MINIZINC",
+        help="Directory containing MiniZinc executable",
+    )
 
 
 def pytest_collect_file(parent, path):