Add Code Quality Analysis via golangci-lint tool, fix detected issues

.golangci.yml

@@ -0,0 +1,4 @@
+issues:
+  exclude:
+    # Check this issue for more info: https://github.com/kyoh86/scopelint/issues/4
+    - Using the variable on range scope `tc` in function literal

.travis.yml

@@ -18,3 +18,6 @@ jobs:
         # Make the binary executable
         - chmod +x $GOPATH/bin/dep
       script: ./hack/ci/run-tests.sh
+    - stage: "Code Quality Analysis"
+      name: tests
+      script: ./hack/ci/run-tests.sh

hack/ci/run-lint.sh

@@ -0,0 +1,46 @@
+#!/usr/bin/env bash
+
+# standard bash error handling
+set -o nounset # treat unset variables as an error and exit immediately.
+set -o errexit # exit immediately when a command fails.
+set -E         # needs to be set if we want the ERR trap
+
+readonly CURRENT_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
+readonly ROOT_PATH=${CURRENT_DIR}/../..
+readonly GOLANGCI_LINT_VERSION="v1.21.0"
+
+source "${CURRENT_DIR}/utilities.sh" || { echo 'Cannot load CI utilities.'; exit 1; }
+
+golangci::install() {
+  shout "Install the golangci-lint in version ${GOLANGCI_LINT_VERSION}"
+  curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | bash -s -- -b "$GOPATH"/bin ${GOLANGCI_LINT_VERSION}
+
+  echo -e "${GREEN}√ install golangci-lint${NC}"
+}
+
+golangci::run_checks() {
+  shout "Run golangci-lint checks"
+  LINTS=(
+    # default golangci-lint lints
+    deadcode errcheck gosimple govet ineffassign staticcheck \
+    structcheck typecheck unused varcheck \
+    # additional lints
+    golint gofmt misspell gochecknoinits unparam scopelint gosec
+  )
+
+  ENABLE=$(sed 's/ /,/g' <<< "${LINTS[@]}")
+
+  golangci-lint --disable-all --enable="${ENABLE}" run ./pkg/... ./cmd/... .
+
+  echo -e "${GREEN}√ run golangci-lint${NC}"
+}
+
+main() {
+  if [[ "${RUN_ON_CI:-x}" == "true" ]]; then
+    golangci::install
+  fi
+
+  golangci::run_checks
+}
+
+main

pkg/codeowners/export_test.go

@@ -12,6 +12,3 @@ func SetFS(newFs afero.Fs) func() {
 
 	return revert
 }
-
-
-

pkg/codeowners/owners_example_test.go

@@ -6,7 +6,7 @@ import (
 	"github.com/mszostok/codeowners-validator/pkg/codeowners"
 )
 
-func ExampleCodeownersEntries() {
+func ExampleNewFromPath() {
 	pathToCodeownersFile := "./testdata/"
 
 	entries, err := codeowners.NewFromPath(pathToCodeownersFile)

pkg/codeowners/owners_test.go

@@ -45,7 +45,8 @@ func TestParseCodeownersSuccess(t *testing.T) {
 	defer revert()
 
 	f, _ := tFS.Create(path.Join(givenCodeownerPath, "CODEOWNERS"))
-	f.WriteString(sampleCodeownerFile)
+	_, err := f.WriteString(sampleCodeownerFile)
+	require.NoError(t, err)
 
 	// when
 	entries, err := codeowners.NewFromPath(givenCodeownerPath)
@@ -82,12 +83,15 @@ func TestFindCodeownersFileSuccess(t *testing.T) {
 			revert := codeowners.SetFS(tFS)
 			defer revert()
 
-			tFS.Create(path.Join(tc.basePath, "CODEOWNERS"))
+			_, err := tFS.Create(path.Join(tc.basePath, "CODEOWNERS"))
+			require.NoError(t, err)
+
 			// when
-			_, err := codeowners.NewFromPath(tc.basePath)
+			entry, err := codeowners.NewFromPath(tc.basePath)
 
 			// then
 			require.NoError(t, err)
+			require.Empty(t, entry)
 		})
 	}
 }