Allow tftest fixtures to run tests in parallel

.github/workflows/tests.yml

@@ -54,7 +54,7 @@ jobs:
       - name: Run tests environments
         id: test-environments
         run: |
-          pytest -n 4 --dist loadfile -vv tests/examples
+          pytest -n 4 -vv tests/examples
 
   tests-examples:
     runs-on: ubuntu-latest
@@ -83,7 +83,7 @@ jobs:
       - name: Run tests examples
         id: test-examples
         run: |
-          pytest -n 4 --dist loadfile -vv tests/modules/examples
+          pytest -n 4 -vv tests/modules/examples
 
   tests-modules:
     runs-on: ubuntu-latest
@@ -112,4 +112,4 @@ jobs:
       - name: Run tests modules
         id: test-modules
         run: |
-          pytest -n 4 --dist loadgroup -vv --ignore=tests/modules/examples tests/modules
+          pytest -n 4 -vv --ignore=tests/modules/examples tests/modules

tests/conftest.py

@@ -15,10 +15,12 @@
 "Shared fixtures"
 
 import os
+import shutil
+import tempfile
+
 import pytest
 import tftest
 
-
 BASEDIR = os.path.dirname(os.path.dirname(__file__))
 
 
@@ -28,10 +30,18 @@ def _plan_runner():
 
   def run_plan(fixture_path, targets=None, refresh=True, **tf_vars):
     "Runs Terraform plan and returns parsed output."
-    tf = tftest.TerraformTest(fixture_path, BASEDIR,
-                              os.environ.get('TERRAFORM', 'terraform'))
-    tf.setup(upgrade=True)
-    return tf.plan(output=True, refresh=refresh, tf_vars=tf_vars, targets=targets)
+    fixture_parent = os.path.dirname(fixture_path)
+    fixture_prefix = os.path.basename(fixture_path) + "_"
+
+    with tempfile.TemporaryDirectory(prefix=fixture_prefix,
+                                     dir=fixture_parent) as tmp_path:
+      # copy fixture to a temporary directory so we can execute
+      # multiple tests in parallel
+      shutil.copytree(fixture_path, tmp_path, dirs_exist_ok=True)
+      tf = tftest.TerraformTest(tmp_path, BASEDIR,
+                                os.environ.get('TERRAFORM', 'terraform'))
+      tf.setup(upgrade=True)
+      return tf.plan(output=True, refresh=refresh, tf_vars=tf_vars, targets=targets)
 
   return run_plan
 
@@ -93,12 +103,20 @@ def apply_runner():
   "Returns a function to run Terraform apply on a fixture."
 
   def run_apply(fixture_path, **tf_vars):
-    "Runs Terraform apply and returns parsed output"
-    tf = tftest.TerraformTest(fixture_path, BASEDIR,
-                              os.environ.get('TERRAFORM', 'terraform'))
-    tf.setup(upgrade=True)
-    apply = tf.apply(tf_vars=tf_vars)
-    output = tf.output(json_format=True)
-    return apply, output
+    "Runs Terraform plan and returns parsed output."
+    fixture_parent = os.path.dirname(fixture_path)
+    fixture_prefix = os.path.basename(fixture_path) + "_"
+
+    with tempfile.TemporaryDirectory(prefix=fixture_prefix,
+                                     dir=fixture_parent) as tmp_path:
+      # copy fixture to a temporary directory so we can execute
+      # multiple tests in parallel
+      shutil.copytree(fixture_path, tmp_path, dirs_exist_ok=True)
+      tf = tftest.TerraformTest(tmp_path, BASEDIR,
+                                os.environ.get('TERRAFORM', 'terraform'))
+      tf.setup(upgrade=True)
+      apply = tf.apply(tf_vars=tf_vars)
+      output = tf.output(json_format=True)
+      return apply, output
 
   return run_apply

tests/requirements.txt

@@ -2,3 +2,4 @@ pytest>=6.2.5
 PyYAML>=6.0
 tftest>=1.6.3
 marko>=1.2.0
+pytest-xdist>=2.5.0