Fix coverage test

The coverage test has been broken since forever [1].

Fix it by updating coverage test to how other projects do it [2][3].

[1] https://zuul.openstack.org/builds?job_name=openstack-tox-cover&project=openstack%2Fpython-magnumclient
[2] https://github.com/openstack/nova/blob/stable/stein/tox.ini#L152-L167
[3] https://github.com/openstack/cinder/blob/stable/stein/tox.ini#L99-L110

Change-Id: I3090e9d9b31dc668d177771de3cf1a8f3ea91ae8

tools/cover.sh

@@ -1,79 +0,0 @@
-#!/bin/bash
-#
-#    Licensed under the Apache License, Version 2.0 (the "License"); you may
-#    not use this file except in compliance with the License. You may obtain
-#    a copy of the License at
-#
-#         http://www.apache.org/licenses/LICENSE-2.0
-#
-#    Unless required by applicable law or agreed to in writing, software
-#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-#    License for the specific language governing permissions and limitations
-#    under the License.
-
-ALLOWED_EXTRA_MISSING=0
-
-show_diff () {
-    head -1 $1
-    diff -U 0 $1 $2 | sed 1,2d
-}
-
-if ! git diff --exit-code || ! git diff --cached --exit-code
-then
-    echo "There are uncommitted changes!"
-    echo "Please clean git working directory and try again"
-    exit 1
-fi
-
-# Checkout master and save coverage report
-git checkout HEAD^
-
-baseline_report=$(mktemp -t magnumclient_coverageXXXXXXX)
-find . -type f -name "*.pyc" -delete
-stestr run "$*"
-coverage combine
-coverage report --fail-under=80 --skip-covered
-coverage html -d cover
-coverage xml -o cover/coverage.xml
-coverage report > $baseline_report
-mv cover cover-master
-cat $baseline_report
-baseline_missing=$(awk 'END { print $3 }' $baseline_report)
-
-# Checkout back and save coverage report
-git checkout -
-
-current_report=$(mktemp -t magnumclient_coverageXXXXXXX)
-find . -type f -name "*.pyc" -delete
-stestr run "$*"
-coverage combine
-coverage report --fail-under=80 --skip-covered
-coverage html -d cover
-coverage xml -o cover/coverage.xml
-coverage report > $current_report
-current_missing=$(awk 'END { print $3 }' $current_report)
-
-# Show coverage details
-allowed_missing=$((baseline_missing+ALLOWED_EXTRA_MISSING))
-
-echo "Allowed to introduce missing lines : ${ALLOWED_EXTRA_MISSING}"
-echo "Missing lines in master            : ${baseline_missing}"
-echo "Missing lines in proposed change   : ${current_missing}"
-
-if [ $allowed_missing -ge $current_missing ]; then
-    if [ $baseline_missing -lt $current_missing ]; then
-        show_diff $baseline_report $current_report
-        echo "We believe you can test your code with 100% coverage!"
-    else
-        echo "Thank you! You are awesome! Keep writing unit tests! :)"
-    fi
-    exit_code=0
-else
-    show_diff $baseline_report $current_report
-    echo "Please write more unit tests, we must maintain our test coverage :( "
-    exit_code=1
-fi
-
-rm $baseline_report $current_report
-exit $exit_code

tox.ini

@@ -60,7 +60,14 @@ commands = {posargs}
 
 [testenv:cover]
 basepython = python3
-commands = {toxinidir}/tools/cover.sh {posargs}
+setenv =
+    PYTHON=coverage run --source magnumclient --parallel-mode
+commands =
+    stestr run {posargs}
+    coverage combine
+    coverage html -d cover
+    coverage xml -o cover/coverage.xml
+    coverage report
 
 [flake8]
 # E123, E125 skipped as they are invalid PEP-8.