test: Add mocking

tools/cli/Makefile

@@ -24,15 +24,16 @@ deps:  ## Download go module dependencies
 .PHONY: devtools
 devtools:  ## Install dev tools
 	@echo "==> Installing dev tools..."
+	go install go.uber.org/mock/mockgen@latest
 	curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(shell go env GOPATH)/bin $(GOLANGCI_VERSION)
 
 .PHONY: setup
 setup: deps devtools ## Set up dev env
 
 .PHONY: fmt
 fmt: ### Format all go files with goimports and gofmt
-	find . -name "*.go" -exec gofmt -w "{}" \;
-	find . -name "*.go" -exec goimports -l -w "{}" \;
+	find . -name "*.go" -not -path "./internal/mocks" -exec gofmt -w "{}" \;
+	find . -name "*.go" -not -path "./internal/mocks" -exec goimports -l -w "{}" \;
 
 .PHONY: build
 build:
@@ -57,6 +58,11 @@ fix-lint: ## Fix linting errors
 list: ## List all make targets
 	@${MAKE} -pRrn : -f $(MAKEFILE_LIST) 2>/dev/null | awk -v RS= -F: '/^# File/,/^# Finished Make data base/ {if ($$1 !~ "^[#.]") {print $$1}}' | egrep -v -e '^[^[:alnum:]]' -e '^$@$$' | sort
 
+.PHONY: gen-mocks
+gen-mocks: ## Generate mocks
+	@echo "==> Generating mocks"
+	rm -rf ./internal/mocks
+	go generate ./internal...
 
 .PHONY: help
 .DEFAULT_GOAL := help

tools/cli/go.mod

@@ -7,6 +7,7 @@ require (
 	github.com/spf13/cobra v1.8.0
 	github.com/stretchr/testify v1.9.0
 	github.com/tufin/oasdiff v1.10.11
+	go.uber.org/mock v0.4.0
 )
 
 require (

tools/cli/go.sum

@@ -48,6 +48,8 @@ github.com/ugorji/go/codec v1.2.11 h1:BMaWp1Bb6fHwEtbplGBGJ498wD+LKlNSl25MjdZY4d
 github.com/ugorji/go/codec v1.2.11/go.mod h1:UNopzCgEMSXjBc6AOMqYvWC1ktqTAfzJZUZgYf6w6lg=
 github.com/yargevad/filepathx v1.0.0 h1:SYcT+N3tYGi+NvazubCNlvgIPbzAk7i7y2dwg3I5FYc=
 github.com/yargevad/filepathx v1.0.0/go.mod h1:BprfX/gpYNJHJfc35GjRRpVcwWXS89gGulUIU5tK3tA=
+go.uber.org/mock v0.4.0 h1:VcM4ZOtdbR4f6VXfiOpwpVJDL6lCReaZ6mw31wqh7KU=
+go.uber.org/mock v0.4.0/go.mod h1:a6FSlNadKUHUa9IP5Vyt1zh4fC7uAwxMutEAscFbkZc=
 golang.org/x/exp v0.0.0-20240119083558-1b970713d09a h1:Q8/wZp0KX97QFTc2ywcOE0YRjZPVIx+MXInMzdvQqcA=
 golang.org/x/exp v0.0.0-20240119083558-1b970713d09a/go.mod h1:idGWGoKP1toJGkd5/ig9ZLuPcZBC3ewk7SzmH0uou08=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

tools/cli/internal/cli/merge/merge.go

@@ -29,14 +29,18 @@ const (
 	DefaultOutputFileName = "FOAS.json"
 )
 
+// writeToFileFunc is a variable that holds the function used to write files.
+// It can be overridden in tests.
+var writeToFileFunc = os.WriteFile
+
 type Opts struct {
 	Merger        openapi.Merger
 	basePath      string
 	outputPath    string
 	externalPaths []string
 }
 
-func (o *Opts) Run(_ []string) error {
+func (o *Opts) Run() error {
 	federated, err := o.Merger.MergeOpenAPISpecs(o.externalPaths)
 	if err != nil {
 		return err
@@ -65,7 +69,7 @@ func (o *Opts) PreRunE(_ []string) error {
 }
 
 func (o *Opts) saveFile(data []byte) error {
-	if err := os.WriteFile(o.outputPath, data, 0o600); err != nil {
+	if err := writeToFileFunc(o.outputPath, data, 0o600); err != nil {
 		return err
 	}
 
@@ -85,8 +89,8 @@ func Builder() *cobra.Command {
 		PreRunE: func(_ *cobra.Command, args []string) error {
 			return opts.PreRunE(args)
 		},
-		RunE: func(_ *cobra.Command, args []string) error {
-			return opts.Run(args)
+		RunE: func(_ *cobra.Command, _ []string) error {
+			return opts.Run()
 		},
 	}
 

tools/cli/internal/cli/merge/merge_test.go

@@ -12,15 +12,52 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build unit
+
 package merge
 
 import (
+	"os"
 	"testing"
 
+	"github.com/getkin/kin-openapi/openapi3"
 	"github.com/mongodb/openapi/tools/cli/internal/cli/flag"
 	"github.com/mongodb/openapi/tools/cli/internal/cli/validator"
+	"github.com/mongodb/openapi/tools/cli/internal/mocks"
+	"github.com/tufin/oasdiff/load"
+	"go.uber.org/mock/gomock"
 )
 
+func TestSuccessfulMerge_Run(t *testing.T) {
+	setupTest(t)
+	ctrl := gomock.NewController(t)
+	mockMergerStore := mocks.NewMockMerger(ctrl)
+
+	externalPaths := []string{"external.json"}
+	opts := &Opts{
+		Merger:        mockMergerStore,
+		basePath:      "base.json",
+		outputPath:    "foas.json",
+		externalPaths: externalPaths,
+	}
+
+	response := &load.SpecInfo{
+		Spec:    &openapi3.T{},
+		Url:     "test",
+		Version: "3.0.1",
+	}
+
+	mockMergerStore.
+		EXPECT().
+		MergeOpenAPISpecs(opts.externalPaths).
+		Return(response, nil).
+		Times(1)
+
+	if err := opts.Run(); err != nil {
+		t.Fatalf("Run() unexpected error: %v", err)
+	}
+}
+
 func TestCreateBuilder(t *testing.T) {
 	validator.ValidateSubCommandsAndFlags(
 		t,
@@ -29,3 +66,10 @@ func TestCreateBuilder(t *testing.T) {
 		[]string{flag.Base, flag.External, flag.Output},
 	)
 }
+
+func setupTest(t *testing.T) {
+	t.Helper()
+	writeToFileFunc = func(_ string, _ []byte, _ os.FileMode) error {
+		return nil
+	}
+}

tools/cli/internal/openapi/errors/path_conflict_error.go

@@ -1,3 +1,17 @@
+// Copyright 2024 MongoDB Inc
+//
+// 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.
+
 package errors
 
 import "fmt"

tools/cli/internal/openapi/oasdiff.go

@@ -1,8 +1,20 @@
+// Copyright 2024 MongoDB Inc
+//
+// 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.
+
 package openapi
 
 import (
-	"log"
-
 	"github.com/mongodb/openapi/tools/cli/internal/openapi/errors"
 	"github.com/tufin/oasdiff/diff"
 	"github.com/tufin/oasdiff/load"
@@ -16,46 +28,6 @@ type OasDiff struct {
 	parser   Parser
 }
 
-func NewOasDiff(base string) (*OasDiff, error) {
-	parser := NewOpenAPI3()
-	baseSpec, err := parser.CreateOpenAPISpecFromPath(base)
-	if err != nil {
-		return nil, err
-	}
-
-	return &OasDiff{
-		base:   baseSpec,
-		parser: parser,
-		config: &diff.Config{
-			IncludePathParams: true,
-		},
-	}, nil
-}
-
-func (o *OasDiff) MergeOpenAPISpecs(paths []string) (*load.SpecInfo, error) {
-	for _, p := range paths {
-		spec, err := o.parser.CreateOpenAPISpecFromPath(p)
-		if err != nil {
-			return nil, err
-		}
-
-		specDiff, err := diff.Get(o.config, o.base.Spec, spec.Spec)
-		if err != nil {
-			log.Fatalf("error in calculating the diff of the specs: %s", err)
-			return nil, err
-		}
-
-		o.specDiff = specDiff
-		o.external = spec
-		err = o.mergeSpecIntoBase()
-		if err != nil {
-			return nil, err
-		}
-	}
-
-	return o.base, nil
-}
-
 func (o OasDiff) mergeSpecIntoBase() error {
 	return o.mergePaths()
 }