pep8: enforce test file names

This is adopted near-verbatim from neutron repo.

Change-Id: Ic3675a7e90893c0ce07404b35efabff750ce9bfe

tools/check_unit_test_structure.sh

@@ -0,0 +1,65 @@
+#!/usr/bin/env bash
+
+# This script identifies the unit test modules that do not correspond
+# directly with a module in the code tree.  See TESTING.rst in neutron
+# repo for the intended structure.
+
+neutron_path=$(cd "$(dirname "$0")/.." && pwd)
+base_test_path=neutron_lib/tests/unit
+test_path=$neutron_path/$base_test_path
+
+test_files=$(find ${test_path} -iname 'test_*.py')
+
+ignore_regexes=(
+    "^test_neutron_lib.py$"
+    "^callbacks/test_callback_exceptions.py$"
+    "^exceptions/test_exceptions.py$"
+    "^api/validators/test_validators.py$"
+    "^api/definitions/test_l3_multi_ext_gw.py$"
+    "^api/definitions/test_l2_adjancency.py$"
+    "^api/definitions/test_bgpvpn_router_assoc_stdattrs.py$"
+    "^api/definitions/test_admin_state_down_before_update.py$"
+    "^api/definitions/test_bgpvpn_net_assoc_stdattrs.py$"
+    "^api/definitions/test_bgpvpn_port_assoc_stdattrs.py$"
+    "^api/definitions/test_segment_peer_subnet_host_routes.py$"
+    "^api/definitions/test_port_hardware_offload.py$"
+    "^api/definitions/test_floating_ip_port_forwarding_port_range.py$"
+    "^api/definitions/test_floating_ip_port_forwarding_extension.py$"
+)
+
+error_count=0
+ignore_count=0
+total_count=0
+for test_file in ${test_files[@]}; do
+    relative_path=${test_file#$test_path/}
+    expected_path=$(dirname $neutron_path/neutron_lib/$relative_path)
+    test_filename=$(basename "$test_file")
+    expected_filename=${test_filename#test_}
+    # Module filename (e.g. foo/bar.py -> foo/test_bar.py)
+    filename=$expected_path/$expected_filename
+    # Package dir (e.g. foo/ -> test_foo.py)
+    package_dir=${filename%.py}
+    if [ ! -f "$filename" ] && [ ! -d "$package_dir" ]; then
+        for ignore_regex in ${ignore_regexes[@]}; do
+            if [[ "$relative_path" =~ $ignore_regex ]]; then
+                ignore_count=$((ignore_count + 1))
+                continue 2
+            fi
+        done
+        echo "Unexpected test file: $base_test_path/$relative_path"
+        error_count=$((error_count + 1))
+    fi
+    total_count=$((total_count + 1))
+done
+
+if [ "$ignore_count" -ne 0 ]; then
+    echo "$ignore_count unmatched test modules were ignored"
+fi
+
+if [ "$error_count" -eq 0 ]; then
+    echo 'Success!  All test modules match targets in the code tree.'
+    exit 0
+else
+    echo "Failure! $error_count of $total_count test modules do not match targets in the code tree."
+    exit 1
+fi

tox.ini

@@ -24,6 +24,7 @@ commands =
 commands =
   flake8
   bash {toxinidir}/tools/check_samples.sh
+  bash {toxinidir}/tools/check_unit_test_structure.sh
   bash ./tools/coding-checks.sh --pylint '{posargs}'
   {[testenv:bandit]commands}