Initial version of presubmit-tests.sh helper in prow-tests image (kna…

…tive#12)

* Initial version of presubmit-tests.sh helper in prow-tests image

This helper manages flag parsing and presubmit skipping, leaving the real script in the repos with only the important stuff (i.e., running the tests themselves).

This will reduce boilerplate code and unify the testing strategy and features for presubmits across ther repos.

* Reorganize source and clarify comments.

images/prow-tests/Dockerfile

@@ -25,3 +25,4 @@ RUN go get github.com/google/go-containerregistry/cmd/ko
 
 # Add our scripts
 ADD scripts/library.sh .
+ADD scripts/presubmit-tests.sh .

images/prow-tests/scripts/presubmit-tests.sh

@@ -0,0 +1,122 @@
+#!/bin/bash
+
+# Copyright 2018 The Knative Authors
+#
+# 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.
+
+# This is a helper script to run the presubmit tests. To use it:
+# 1. Source this script.
+# 2. Define the functions build_tests(), unit_tests() and
+#    integration_tests(). They should run all tests (i.e., not fail
+#    fast), and return 0 if all passed, 1 if a failure occurred.
+#    The environment variables RUN_BUILD_TESTS, RUN_UNIT_TESTS and
+#    RUN_INTEGRATION_TESTS are set to 0 (false) or 1 (true) accordingly.
+#    If --emit-metrics is passed, EMIT_METRICS will be set to 1.
+# 3. Call the main() function passing $@ (without quotes).
+#
+# Running the script without parameters, or with the --all-tests
+# flag, causes all tests to be executed, in the right order.
+# Use the flags --build-tests, --unit-tests and --integration-tests
+# to run a specific set of tests. The flag --emit-metrics is used
+# to emit metrics when running the tests.
+
+# Load github.com/knative/test-infra/images/prow-tests/scripts/library.sh
+[ -f /workspace/library.sh ] \
+  && source /workspace/library.sh \
+  || eval "$(docker run --entrypoint sh gcr.io/knative-tests/test-infra/prow-tests -c 'cat library.sh')"
+[ -v KNATIVE_TEST_INFRA ] || exit 1
+
+# Extensions or file patterns that don't require presubmit tests.
+readonly NO_PRESUBMIT_FILES=(\.md \.png ^OWNERS)
+
+# Options set by command-line flags.
+RUN_BUILD_TESTS=0
+RUN_UNIT_TESTS=0
+RUN_INTEGRATION_TESTS=0
+EMIT_METRICS=0
+
+# Exit presubmit tests if only documentation files were changed.
+function exit_if_presubmit_not_required() {
+  if [[ -n "${PULL_PULL_SHA}" ]]; then
+    # On a presubmit job
+    local changes="$(git diff --name-only ${PULL_PULL_SHA} ${PULL_BASE_SHA})"
+    local no_presubmit_pattern="${NO_PRESUBMIT_FILES[*]}"
+    local no_presubmit_pattern="\(${no_presubmit_pattern// /\\|}\)$"
+    echo -e "Changed files in commit ${PULL_PULL_SHA}:\n${changes}"
+    if [[ -z "$(echo "${changes}" | grep -v ${no_presubmit_pattern})" ]]; then
+      # Nothing changed other than files that don't require presubmit tests
+      header "Commit only contains changes that don't affect tests, skipping"
+      exit 0
+    fi
+  fi
+}
+
+# Process flags and run tests accordingly.
+function main() {
+  exit_if_presubmit_not_required
+
+  local all_parameters=$@
+  [[ -z $1 ]] && all_parameters="--all-tests"
+
+  for parameter in ${all_parameters}; do
+    case ${parameter} in
+      --all-tests)
+        RUN_BUILD_TESTS=1
+        RUN_UNIT_TESTS=1
+        RUN_INTEGRATION_TESTS=1
+        shift
+        ;;
+      --build-tests)
+        RUN_BUILD_TESTS=1
+        shift
+        ;;
+      --unit-tests)
+        RUN_UNIT_TESTS=1
+        shift
+        ;;
+      --integration-tests)
+        RUN_INTEGRATION_TESTS=1
+        shift
+        ;;
+      --emit-metrics)
+        EMIT_METRICS=1
+        shift
+        ;;
+      *)
+        echo "error: unknown option ${parameter}"
+        exit 1
+        ;;
+    esac
+  done
+
+  readonly RUN_BUILD_TESTS
+  readonly RUN_UNIT_TESTS
+  readonly RUN_INTEGRATION_TESTS
+  readonly EMIT_METRICS
+
+  cd ${REPO_ROOT_DIR}
+
+  # Tests to be performed, in the right order if --all-tests is passed.
+
+  local result=0
+  if (( RUN_BUILD_TESTS )); then
+    build_tests || result=1
+  fi
+  if (( RUN_UNIT_TESTS )); then
+    unit_tests || result=1
+  fi
+  if (( RUN_INTEGRATION_TESTS )); then
+    integration_tests || result=1
+  fi
+  exit ${result}
+}