diff --git a/.golangci.yml b/.golangci.yml
new file mode 100644
index 0000000..92b00d1
--- /dev/null
+++ b/.golangci.yml
@@ -0,0 +1,87 @@
+run:
+  timeout: 3m
+
+linters-settings:
+  goconst:
+    min-len: 3
+    min-occurrences: 3
+  gocritic:
+    enabled-tags:
+      - diagnostic
+      - experimental
+      - opinionated
+      - performance
+      - style
+    disabled-checks:
+      - dupImport # https://github.com/go-critic/go-critic/issues/845
+      - ifElseChain
+      - octalLiteral
+      - whyNoLint
+      - wrapperFunc
+      - importShadow
+      - unnamedResult
+      - unnecessaryBlock
+    settings:
+      rangeValCopy:
+        sizeThreshold: 256
+      hugeParam:
+        sizeThreshold: 256
+  gocyclo:
+    min-complexity: 16
+  goimports:
+    local-prefixes: github.com/golangci/golangci-lint
+  golint:
+    min-confidence: 0
+  govet:
+    check-shadowing: true
+  lll:
+    line-length: 300
+  maligned:
+    suggest-new: true
+  misspell:
+    locale: US
+  nolintlint:
+    allow-leading-space: true # don't require machine-readable nolint directives (i.e. with no leading space)
+    allow-unused: false # report any unused nolint directives
+    require-explanation: false # don't require an explanation for nolint directives
+    require-specific: false # don't require nolint directives to be specific about which linter is being skipped
+
+linters:
+  disable-all: true
+  enable:
+    - asciicheck
+    - bodyclose
+    - deadcode
+    - depguard
+    - dogsled
+    - dupl
+    - errcheck
+    - gochecknoinits
+    - goconst
+    - gocritic
+    - gofmt
+    - goimports
+    - golint
+    - goprintffuncname
+    - gosec
+    - gosimple
+    - govet
+    - ineffassign
+    - interfacer
+    - lll
+    - maligned
+    - misspell
+    - nakedret
+    - nolintlint
+    - prealloc
+    - rowserrcheck
+    - scopelint
+    - staticcheck
+    - structcheck
+    - stylecheck
+    - typecheck
+    - unconvert
+    - unparam
+    - unused
+    - varcheck
+    - whitespace
\ No newline at end of file
diff --git a/.travis.yml b/.travis.yml
index ff3dd13..55fe05c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,19 +1,4 @@
 language: go
 
 go:
-  - 1.12.x
-
-env:
-  - GO111MODULE=on
-
-before_install:
-  - go get golang.org/x/lint/golint
-
-install:
-# skip
-
-script:
-  - go get -v ./...
-  - go vet ./...
-  - golint -set_exit_status ./...
-  - go test -v ./...
+  - 1.14.x
\ No newline at end of file
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..c54c53e
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,21 @@
+# Changelog
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+## [1.1.0] - 07-15-20
+### Added
+- Added golangci-lint linter, Makefile, and fixed linter warnings
+
+### Changed
+- go-groups now runs gofmt over the input files, unless disabled by the `-f` flag.
+
+### Fixed
+- Fixed go-groups stripping the dot from dot imports (thanks [@jdroot](https://github.com/jdroot))
+- Fixed go-groups removing comments and other content from import blocks
+
+## [1.0.3] - 2019-06-20
+Initial public release
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..b64c632
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,31 @@
+BIN_DIR         ?= $(shell go env GOPATH)/bin
+
+default: test
+
+deps: ## download go modules
+	go mod download
+
+fmt: lint/install # ensure consistent code style
+	gofmt -s -w .
+	golangci-lint run --fix > /dev/null 2>&1 || true
+
+lint/install:
+	@if ! golangci-lint --version > /dev/null 2>&1; then \
+	  echo "Installing golangci-lint"; \
+	  curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | sh -s -- -b $(BIN_DIR) v1.28.3; \
+	fi
+
+lint: lint/install ## run golangci-lint
+	@if ! golangci-lint run; then \
+  		echo "\033[0;33mdetected fmt problems: run \`\033[0;32mmake fmt\033[0m\`"; \
+  		exit 1; \
+  	fi
+
+test: lint ## run go tests
+	go vet ./...
+	go test ./... -race
+
+help: ## displays this help message
+	@awk 'BEGIN {FS = ":.*?## "} /^[a-zA-Z_\/-]+:.*?## / {printf "\033[34m%-30s\033[0m %s\n", $$1, $$2}' $(MAKEFILE_LIST) | \
+		sort | \
+		grep -v '#'
diff --git a/README.md b/README.md
index 2b4a09b..6db14c3 100644
--- a/README.md
+++ b/README.md
@@ -15,6 +15,8 @@ the imports.
 
 `go-groups` is similar to `goimports`, but in addition to sorting imports 
 lexigraphically, it also separates import blocks at a per-project level.
+Like `goimports`, `go-groups` also runs gofmt and fixes any style/formatting
+issues.
 
 
 # Getting Started
@@ -51,8 +53,7 @@ import (
 
 #### Typical Workflow
 
-1. Run `go-groups -w ./..` to rewrite and sort import groupings
-2. Run `gofmt -w ./..` to format your go source file
+Run `go-groups -w ./..` to rewrite and sort import groupings for go source files in a project.
 
 #### More info
 
diff --git a/go.mod b/go.mod
index d1bb49a..ce9b907 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,7 @@
 module oss.indeed.com/go/go-groups
 
+go 1.14
+
 require (
-	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/stretchr/testify v1.3.0
+	github.com/stretchr/testify v1.6.1
 )
diff --git a/go.sum b/go.sum
index 4f76e62..56d62e7 100644
--- a/go.sum
+++ b/go.sum
@@ -1,9 +1,10 @@
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
-github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
-github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd0=
+github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/gofmt.go b/gofmt.go
index e4f5b12..9ae8bd2 100644
--- a/gofmt.go
+++ b/gofmt.go
@@ -33,6 +33,7 @@ package main
 import (
 	"bytes"
 	"fmt"
+	"go/scanner"
 	"io"
 	"io/ioutil"
 	"os"
@@ -44,8 +45,14 @@ import (
 
 // based on https://golang.org/src/cmd/gofmt/gofmt.go with a few modifications
 
+func isGoFile(f os.FileInfo) bool {
+	// ignore non-Go files
+	name := f.Name()
+	return !f.IsDir() && !strings.HasPrefix(name, ".") && strings.HasSuffix(name, ".go")
+}
+
 // If in == nil, the source is the contents of the file with the given filename.
-func processFile(filename string, in io.Reader, out io.Writer) error {
+func processFile(filename string, in io.Reader, out io.Writer, fixFmt bool) error {
 	var perm os.FileMode = 0644
 	if in == nil {
 		f, err := os.Open(filename)
@@ -66,26 +73,35 @@ func processFile(filename string, in io.Reader, out io.Writer) error {
 		return err
 	}
 
-	result, rewrite := parse(src)
-	// nothing to do, file has no imports
-	if !rewrite {
-		return nil
+	if fixFmt {
+		buffer := bytes.Buffer{}
+		buffer.Write(src)
+		cmd := exec.Command("gofmt", "--")
+		cmd.Stdin = &buffer
+		cmd.Stderr = os.Stderr
+		src, err = cmd.Output()
+		if err != nil {
+			return err
+		}
 	}
 
-	// something to do
-	if !bytes.Equal(src, result) {
+	res, rewritten := parse(src)
+	if !bytes.Equal(src, res) && rewritten {
+		// formatting has changed
 		if *list {
-			fmt.Fprintln(out, filename)
+			if _, err := fmt.Fprintln(out, filename); err != nil { //nolint:govet
+				return err
+			}
 		}
 		if *write {
 			// make a temporary backup before overwriting original
-			bakname, err := backupFile(filename+".", src, perm)
+			bakname, err := backupFile(filename+".", src, perm) //nolint:govet
 			if err != nil {
 				return err
 			}
-			err = ioutil.WriteFile(filename, result, perm)
+			err = ioutil.WriteFile(filename, res, perm)
 			if err != nil {
-				os.Rename(bakname, filename)
+				_ = os.Rename(bakname, filename)
 				return err
 			}
 			err = os.Remove(bakname)
@@ -94,29 +110,33 @@ func processFile(filename string, in io.Reader, out io.Writer) error {
 			}
 		}
 		if *doDiff {
-			data, err := diff(src, result, filename)
+			data, err := diff(src, res, filename) //nolint:govet
 			if err != nil {
 				return fmt.Errorf("computing diff: %s", err)
 			}
 			fmt.Printf("diff -u %s %s\n", filepath.ToSlash(filename+".orig"), filepath.ToSlash(filename))
-			out.Write(data)
+			_, err = out.Write(data)
+			if err != nil {
+				return err
+			}
 		}
 	}
 
 	if !*list && !*write && !*doDiff {
-		_, err = out.Write(result)
+		_, err = out.Write(res)
 	}
+
 	return err
 }
 
 func visitFile(path string, f os.FileInfo, err error) error {
 	if err == nil && isGoFile(f) {
-		err = processFile(path, nil, os.Stdout)
+		err = processFile(path, nil, os.Stdout, !*noFormat)
 	}
 	// Don't complain if a file was deleted in the meantime (i.e.
-	// the directory changed concurrently while running).
+	// the directory changed concurrently while running gofmt).
 	if err != nil && !os.IsNotExist(err) {
-		return err
+		scanner.PrintError(os.Stderr, err)
 	}
 	return nil
 }
@@ -125,28 +145,6 @@ func walkDir(path string) error {
 	return filepath.Walk(path, visitFile)
 }
 
-func isGoFile(f os.FileInfo) bool {
-	// ignore non-Go files
-	name := f.Name()
-	return !f.IsDir() && !strings.HasPrefix(name, ".") && strings.HasSuffix(name, ".go")
-}
-
-func writeTempFile(dir, prefix string, data []byte) (string, error) {
-	file, err := ioutil.TempFile(dir, prefix)
-	if err != nil {
-		return "", err
-	}
-	_, err = file.Write(data)
-	if err1 := file.Close(); err == nil {
-		err = err1
-	}
-	if err != nil {
-		os.Remove(file.Name())
-		return "", err
-	}
-	return file.Name(), nil
-}
-
 func diff(b1, b2 []byte, filename string) (data []byte, err error) {
 	f1, err := writeTempFile("", "go-groups", b1)
 	if err != nil {
@@ -174,6 +172,22 @@ func diff(b1, b2 []byte, filename string) (data []byte, err error) {
 	return
 }
 
+func writeTempFile(dir, prefix string, data []byte) (string, error) {
+	file, err := ioutil.TempFile(dir, prefix)
+	if err != nil {
+		return "", err
+	}
+	_, err = file.Write(data)
+	if err1 := file.Close(); err == nil {
+		err = err1
+	}
+	if err != nil {
+		os.Remove(file.Name())
+		return "", err
+	}
+	return file.Name(), nil
+}
+
 // replaceTempFilename replaces temporary filenames in diff with actual one.
 //
 // --- /tmp/gofmt316145376	2017-02-03 19:13:00.280468375 -0500
diff --git a/gofmt_test.go b/gofmt_test.go
index d16f2d6..8f5a9cd 100644
--- a/gofmt_test.go
+++ b/gofmt_test.go
@@ -42,8 +42,6 @@ import (
 )
 
 // based on https://golang.org/src/cmd/gofmt/gofmt_test.go with a few modifications
-
-
 func TestBackupFile(t *testing.T) {
 	dir, err := ioutil.TempDir("", "gofmt_test")
 	if err != nil {
diff --git a/import.go b/import.go
index e4ca2cd..ad2ad2f 100644
--- a/import.go
+++ b/import.go
@@ -6,8 +6,8 @@ import (
 )
 
 // Imports represents the list of imports in a given go file.
-// This helper encapsulates the logic for sorting immports based on go-groups.
-type Imports []string
+// This helper encapsulates the logic for sorting imports based on go-groups.
+type Imports []importLine
 
 var _ sort.Interface = (*Imports)(nil)
 
@@ -20,11 +20,11 @@ func (s Imports) Swap(i, j int) {
 }
 
 func (s Imports) Less(i, j int) bool {
-	s1 := strings.TrimSpace(s[i])
+	s1 := strings.TrimSpace(s[i].line)
 	if strings.ContainsAny(s1, " ") {
 		s1 = strings.Join(strings.Split(s1, " ")[1:], " ")
 	}
-	s2 := strings.TrimSpace(s[j])
+	s2 := strings.TrimSpace(s[j].line)
 	if strings.ContainsAny(s2, " ") {
 		s2 = strings.Join(strings.Split(s2, " ")[1:], " ")
 	}
diff --git a/main.go b/main.go
index 98293f7..f9b95e5 100644
--- a/main.go
+++ b/main.go
@@ -16,7 +16,7 @@ const (
 	exitBadStdin      = 2
 	exitInternalError = 3
 
-	versionStr = "go-groups version 1.0.3 (2019-06-20)"
+	versionStr = "go-groups version 1.1.0 (2020-07-15)"
 )
 
 var (
@@ -24,13 +24,14 @@ var (
 	importEndRegex   = regexp.MustCompile(`^\s*\)\s*$`)
 
 	// any whitespace + any unicode_letter_or_underscore + any unicode_letter_or_underscore_or_unicode number + any whitespace + quote + any + quote + any
-	groupedImportRegex = regexp.MustCompile(`^\s*[\p{L}_]*[\s*[\p{L}_\p{N}]*\s*".*".*$`)
+	groupedImportRegex = regexp.MustCompile(`^\s*[\p{L}_\\.]*[\s*[\p{L}_\p{N}]*\s*".*".*$`)
 	externalImport     = regexp.MustCompile(`"([a-zA-Z0-9_]{1}[a-zA-Z0-9_-]{0,62}){1}(\.[a-zA-Z0-9_]{1}[a-zA-Z0-9_-]{0,62})*[\._]?\/([\p{L}_\-\p{N}]*)\/?.*"`)
 
-	list    = flag.Bool("l", false, "list files whose formatting differs")
-	write   = flag.Bool("w", false, "write result to (source) file instead of stdout")
-	doDiff  = flag.Bool("d", false, "display diffs instead of rewriting files")
-	version = flag.Bool("v", false, "display the version of go-groups")
+	list     = flag.Bool("l", false, "list files whose formatting differs")
+	write    = flag.Bool("w", false, "write result to (source) file instead of stdout")
+	doDiff   = flag.Bool("d", false, "display diffs instead of rewriting files")
+	version  = flag.Bool("v", false, "display the version of go-groups")
+	noFormat = flag.Bool("f", false, "disables the automatic gofmt style fixes")
 )
 
 func main() {
@@ -48,7 +49,7 @@ func main() {
 			_, _ = fmt.Fprintln(os.Stderr, "error: cannot use -w with standard input")
 			os.Exit(exitBadStdin)
 		}
-		if err := processFile("<standard input>", os.Stdin, os.Stdout); err != nil {
+		if err := processFile("<standard input>", os.Stdin, os.Stdout, !*noFormat); err != nil {
 			_, _ = fmt.Fprintln(os.Stderr, "failed to parse stdin: "+err.Error())
 			os.Exit(exitBadFlags)
 		}
@@ -67,7 +68,7 @@ func main() {
 				os.Exit(exitInternalError)
 			}
 		default:
-			_ = processFile(path, nil, os.Stdout)
+			_ = processFile(path, nil, os.Stdout, !*noFormat)
 		}
 	}
 }
@@ -81,7 +82,13 @@ type importGroup struct {
 	lineStart int
 	lineEnd   int
 
-	lines []string
+	lines []importLine
+}
+
+type importLine struct {
+	line         string
+	contentAbove string
+	contentBelow string
 }
 
 func parse(src []byte) (result []byte, rewritten bool) {
@@ -89,10 +96,15 @@ func parse(src []byte) (result []byte, rewritten bool) {
 	contents := make(map[int]string, 128)
 
 	scanner := bufio.NewScanner(bytes.NewReader(src))
+	lines := make([]string, 0, 128)
+	for scanner.Scan() {
+		lines = append(lines, scanner.Text())
+	}
 
 	insideImports := false
 	var n int
 	var group importGroup
+	scanner = bufio.NewScanner(bytes.NewReader(src))
 	for n = 0; scanner.Scan(); n++ {
 		line := scanner.Text()
 		if insideImports {
@@ -101,7 +113,34 @@ func parse(src []byte) (result []byte, rewritten bool) {
 				group.lineEnd = n
 				groups = append(groups, group)
 			} else if groupedImportRegex.MatchString(line) {
-				group.lines = append(group.lines, line)
+				importLine := importLine{ //nolint:govet
+					line: line,
+				}
+				var above, below int
+				for above = n - 1; above > 0; above-- {
+					if groupedImportRegex.MatchString(lines[above]) || importStartRegex.MatchString(lines[above]) {
+						above++
+						break
+					}
+				}
+				for below = n + 1; below < len(lines); below++ {
+					if importEndRegex.MatchString(lines[below]) {
+						below--
+						break
+					}
+					// if we hit an import beneath us, assume it owns the non-import content above itself, not us
+					if groupedImportRegex.MatchString(lines[below]) {
+						below = n
+						break
+					}
+				}
+				if above != n {
+					importLine.contentAbove = strings.Join(filterNewlines(lines[above:n]), "\n")
+				}
+				if below != n {
+					importLine.contentBelow = strings.Join(filterNewlines(lines[n+1:below+1]), "\n")
+				}
+				group.lines = append(group.lines, importLine)
 			}
 		} else if importStartRegex.MatchString(line) {
 			insideImports = true
@@ -127,6 +166,16 @@ func parse(src []byte) (result []byte, rewritten bool) {
 	return fileBytes, true
 }
 
+func filterNewlines(lines []string) []string {
+	filtered := make([]string, 0, len(lines))
+	for _, line := range lines {
+		if strings.TrimSpace(line) != "" {
+			filtered = append(filtered, line)
+		}
+	}
+	return filtered
+}
+
 func fixupFile(contents map[int]string, numLines int, groups []importGroup) []byte {
 	buffer := bytes.NewBufferString("")
 	for i := 0; i < numLines; i++ {
@@ -137,22 +186,31 @@ func fixupFile(contents map[int]string, numLines int, groups []importGroup) []by
 			continue
 		}
 		for _, group := range groups {
-			if group.lineStart == i {
-				buffer.WriteString("import (\n")
-				leadingWhitespace := true
-				for _, line := range group.lines {
-					if leadingWhitespace && strings.TrimSpace(line) == "" {
-						// skip empty leading import lines
-					} else {
-						buffer.WriteString(line)
+			if group.lineStart != i {
+				continue
+			}
+			buffer.WriteString("import (\n")
+			leadingWhitespace := true
+			for _, importLine := range group.lines {
+				if leadingWhitespace && strings.TrimSpace(importLine.line) == "" {
+					// skip empty leading import lines
+				} else {
+					if importLine.contentAbove != "" {
+						buffer.WriteString(importLine.contentAbove)
+						buffer.WriteString("\n")
+					}
+					buffer.WriteString(importLine.line)
+					buffer.WriteString("\n")
+					if importLine.contentBelow != "" {
+						buffer.WriteString(importLine.contentBelow)
 						buffer.WriteString("\n")
-						leadingWhitespace = false
 					}
+					leadingWhitespace = false
 				}
-				buffer.WriteString(")\n")
-				i = group.lineEnd
-				break
 			}
+			buffer.WriteString(")\n")
+			i = group.lineEnd
+			break
 		}
 	}
 	return buffer.Bytes()
@@ -167,11 +225,11 @@ func regroupImportGroups(group importGroup) importGroup {
 	standardImports := make(Imports, 0, len(group.lines))
 
 	sortedKeys := make([]string, 0)
-	groupNames := make(map[string]Imports, 0)
+	groupNames := make(map[string]Imports)
 	for _, importLine := range group.lines {
-		matches := externalImport.FindStringSubmatch(importLine)
+		matches := externalImport.FindStringSubmatch(importLine.line)
 
-		if matches != nil && strings.ContainsAny(importLine, ".") {
+		if matches != nil && strings.ContainsAny(importLine.line, ".") {
 			groupName := strings.Join(matches[1:], "")
 			if groupNames[groupName] == nil {
 				groupNames[groupName] = make(Imports, 0, 1)
@@ -190,7 +248,7 @@ func regroupImportGroups(group importGroup) importGroup {
 		imports := groupNames[groupName]
 		sort.Sort(imports)
 
-		group.lines = append(group.lines, "")
+		group.lines = append(group.lines, importLine{})
 		group.lines = append(group.lines, imports...)
 	}
 	return group
diff --git a/main_test.go b/main_test.go
index 22c0a9c..e856378 100644
--- a/main_test.go
+++ b/main_test.go
@@ -1,280 +1,110 @@
 package main
 
 import (
+	"bytes"
+	"io/ioutil"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/require"
 )
 
-// TODO: move the import blocks to test fixtures, this file is pretty unreadable
-
 func TestParse_NoImports(t *testing.T) {
 	_, rewritten := parse([]byte(""))
 	require.False(t, rewritten)
 }
 
 func TestParse_ValidGroupingSortImports(t *testing.T) {
-	str :=
-		`
-package foo
-
-import (
-	"fmt"
-	"io"
-	"io/ioutil"
-	"os"
-	"strconv"
-	"strings"
-)
-`
-
-	result, rewritten := parse([]byte(str))
+	bytes := testdata(t, "valid_imports.txt")
+	result, rewritten := parse(bytes)
 
 	require.True(t, rewritten)
-	require.Equal(t, str, string(result))
+	require.Equal(t, string(bytes), string(result))
 }
 
 func TestParse_ExtraGroups(t *testing.T) {
-	str :=
-		`
-package foo
-
-import (
-	"io"
-	"strings"
-
-	"strconv"
-	"fmt"
-
-	"os"
-	"io/ioutil"
-)
-`
-
-	expected :=
-		`
-package foo
-
-import (
-	"fmt"
-	"io"
-	"io/ioutil"
-	"os"
-	"strconv"
-	"strings"
-)
-`
-	result, rewritten := parse([]byte(str))
+	bytes := testdata(t, "extra_groups.txt")
+	result, rewritten := parse(bytes)
 
 	require.True(t, rewritten)
-	require.Equal(t, expected, string(result))
+	require.Equal(t, testdata(t, "valid_imports.txt"), result)
 }
 
 func TestParse_ExternalGroups(t *testing.T) {
-	str :=
-		`
-package foo
-
-import (
-	"io"
-	"strings"
-	"strconv"
-	"fmt"
-	"os"
-	"io/ioutil"
-
-	"indeed.com/devops/foobar"
-
-	"indeed.com/gophers/quz"
-
-	"github.com/hashicorp/vault/x"
-
-)
-`
-
-	expected :=
-		`
-package foo
-
-import (
-	"fmt"
-	"io"
-	"io/ioutil"
-	"os"
-	"strconv"
-	"strings"
-
-	"github.com/hashicorp/vault/x"
-
-	"indeed.com/devops/foobar"
-
-	"indeed.com/gophers/quz"
-)
-`
-	result, rewritten := parse([]byte(str))
+	bytes := testdata(t, "external_groups_invalid.txt")
+	expected := testdata(t, "external_groups.txt")
+	result, rewritten := parse(bytes)
 
 	require.True(t, rewritten)
-	require.Equal(t, expected, string(result))
+	require.Equal(t, string(expected), string(result))
 }
 
 func TestParse_SortingExternalGroups(t *testing.T) {
-	str :=
-		`
-package foo
-
-import (
-    "net/http"
-    "testing"
-
-    "indeed.com/devops/libmarvin/gin/ginhandler"
-    "indeed.com/devops/libmarvin/spec"
-    "indeed.com/devops/marvlet/api/v2"
- 
-    "github.com/gin-gonic/gin"
-    "github.com/stretchr/testify/suite"
-)
-`
-
-	expected :=
-		`
-package foo
-
-import (
-    "net/http"
-    "testing"
-
-    "github.com/gin-gonic/gin"
-
-    "github.com/stretchr/testify/suite"
-
-    "indeed.com/devops/libmarvin/gin/ginhandler"
-    "indeed.com/devops/libmarvin/spec"
-    "indeed.com/devops/marvlet/api/v2"
-)
-`
-	result, rewritten := parse([]byte(str))
+	bytes := testdata(t, "sort_external_groups_invalid.txt")
+	expected := testdata(t, "sort_external_groups.txt")
+	result, rewritten := parse(bytes)
 
 	require.True(t, rewritten)
-	require.Equal(t, expected, string(result))
+	require.Equal(t, expected, result)
 }
 
 func TestParse_PrefixedGroups(t *testing.T) {
-	str :=
-		`
-package foo
-
-import (
-	"fmt"
-	"os/user"
-	"strconv"
-	"strings"
-	"time"
-
-	"github.com/pkg/errors"
-	"indeed.com/gophers/libarc"
-	"indeed.com/gophers/libops"
-	"indeed.com/gophers/rlog"
-
-	"indeed.com/devops/libmarvin/spec"
-	"indeed.com/devops/marvlet/backend"
-	"indeed.com/devops/marvlet/backend/indeed"
-
-	appsv1 "k8s.io/api/apps/v1"
-	apiv1 "k8s.io/api/core/v1"
-
-	"k8s.io/apimachinery/pkg/api/resource"
-	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/apimachinery/pkg/types"
-	"k8s.io/apimachinery/pkg/util/intstr"
-
-	"k8s.io/client-go/kubernetes"
-	"k8s.io/client-go/kubernetes/typed/apps/v1"
-)
-`
-	expected :=
-		`
-package foo
-
-import (
-	"fmt"
-	"os/user"
-	"strconv"
-	"strings"
-	"time"
-
-	"github.com/pkg/errors"
-
-	"indeed.com/devops/libmarvin/spec"
-	"indeed.com/devops/marvlet/backend"
-	"indeed.com/devops/marvlet/backend/indeed"
-
-	"indeed.com/gophers/libarc"
-	"indeed.com/gophers/libops"
-	"indeed.com/gophers/rlog"
-
-	appsv1 "k8s.io/api/apps/v1"
-	apiv1 "k8s.io/api/core/v1"
-
-	"k8s.io/apimachinery/pkg/api/resource"
-	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"k8s.io/apimachinery/pkg/types"
-	"k8s.io/apimachinery/pkg/util/intstr"
-
-	"k8s.io/client-go/kubernetes"
-	"k8s.io/client-go/kubernetes/typed/apps/v1"
-)
-`
-	result, rewritten := parse([]byte(str))
+	bytes := testdata(t, "prefixed_groups_invalid.txt")
+	expected := testdata(t, "prefixed_groups.txt")
+	result, rewritten := parse(bytes)
 
 	require.True(t, rewritten)
-	require.Equal(t, expected, string(result))
+	require.Equal(t, expected, result)
 }
 
 func TestParse_SubdomainImports(t *testing.T) {
-	str :=
-		`
-package foo
+	bytes := testdata(t, "subdomain_imports_invalid.txt")
+	expected := testdata(t, "subdomain_imports.txt")
+	result, rewritten := parse(bytes)
 
-import (
-	"context"
-	"io"
-	"net/http"
-	"strconv"
-	"strings"
-
-	"github.com/grpc-ecosystem/grpc-gateway/runtime"
+	require.True(t, rewritten)
+	require.Equal(t, string(expected), string(result))
+}
 
-	"github.com/shoenig/petrify/v4"
+func TestParse_CommentedImports(t *testing.T) {
+	bytes := testdata(t, "commented_imports.txt")
+	result, rewritten := parse(bytes)
+	require.True(t, rewritten)
+	require.Equal(t, string(bytes), string(result))
+}
 
-	"golang.org/x/net/http2"
-	"golang.org/x/net/http2/h2c"
-	"google.golang.org/grpc"
-)
-`
+func TestParse_Multiline_CommentedImports(t *testing.T) {
+	bytes := testdata(t, "multiline_comments_invalid.txt")
+	expected := testdata(t, "multiline_comments.txt")
+	result, rewritten := parse(bytes)
+	require.True(t, rewritten)
+	require.Equal(t, string(expected), string(result))
+}
 
-	expected :=
-		`
-package foo
+func TestParse_gofmt(t *testing.T) {
+	b := testdata(t, "gofmt_invalid.txt")
+	expected := testdata(t, "gofmt.txt")
 
-import (
-	"context"
-	"io"
-	"net/http"
-	"strconv"
-	"strings"
+	var buf bytes.Buffer
+	err := processFile("", strings.NewReader(string(b)), &buf, true)
+	require.NoError(t, err)
 
-	"github.com/grpc-ecosystem/grpc-gateway/runtime"
+	require.Equal(t, string(expected), buf.String())
+}
 
-	"github.com/shoenig/petrify/v4"
+func TestParse_gofmt_disabled(t *testing.T) {
+	b := testdata(t, "gofmt_invalid.txt")
+	expected := testdata(t, "gofmt_invalid.txt")
 
-	"golang.org/x/net/http2"
-	"golang.org/x/net/http2/h2c"
+	var buf bytes.Buffer
+	err := processFile("", strings.NewReader(string(b)), &buf, false)
+	require.NoError(t, err)
 
-	"google.golang.org/grpc"
-)
-`
-	result, rewritten := parse([]byte(str))
+	require.Equal(t, string(expected), buf.String())
+}
 
-	require.True(t, rewritten)
-	require.Equal(t, expected, string(result))
+func testdata(t *testing.T, str string) []byte {
+	b, err := ioutil.ReadFile("testdata/" + str)
+	require.NoError(t, err)
+	return b
 }
diff --git a/testdata/commented_imports.txt b/testdata/commented_imports.txt
new file mode 100644
index 0000000..3570927
--- /dev/null
+++ b/testdata/commented_imports.txt
@@ -0,0 +1,10 @@
+package main
+
+import (
+	"fmt"
+	// example comment
+)
+
+func main() {
+	fmt.Println("Hello world")
+}
diff --git a/testdata/external_groups.txt b/testdata/external_groups.txt
new file mode 100644
index 0000000..c59bf44
--- /dev/null
+++ b/testdata/external_groups.txt
@@ -0,0 +1,16 @@
+package foo
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/hashicorp/vault/x"
+
+	"indeed.com/devops/foobar"
+
+	"indeed.com/gophers/quz"
+)
diff --git a/testdata/external_groups_invalid.txt b/testdata/external_groups_invalid.txt
new file mode 100644
index 0000000..acdbab9
--- /dev/null
+++ b/testdata/external_groups_invalid.txt
@@ -0,0 +1,17 @@
+package foo
+
+import (
+	"io"
+	"strings"
+	"strconv"
+	"fmt"
+	"os"
+	"io/ioutil"
+
+	"indeed.com/devops/foobar"
+
+	"indeed.com/gophers/quz"
+
+	"github.com/hashicorp/vault/x"
+
+)
diff --git a/testdata/extra_groups.txt b/testdata/extra_groups.txt
new file mode 100644
index 0000000..3a362dd
--- /dev/null
+++ b/testdata/extra_groups.txt
@@ -0,0 +1,12 @@
+package foo
+
+import (
+	"fmt"
+	"strings"
+
+	"io"
+	"io/ioutil"
+
+	"os"
+	"strconv"
+)
diff --git a/testdata/gofmt.txt b/testdata/gofmt.txt
new file mode 100644
index 0000000..5565343
--- /dev/null
+++ b/testdata/gofmt.txt
@@ -0,0 +1,14 @@
+package main
+
+import (
+	"fmt"
+)
+
+var (
+	foo = "misaligned"
+	bar = "variables"
+)
+
+func main() {
+	fmt.Println("Hello world")
+}
diff --git a/testdata/gofmt_invalid.txt b/testdata/gofmt_invalid.txt
new file mode 100644
index 0000000..cc93141
--- /dev/null
+++ b/testdata/gofmt_invalid.txt
@@ -0,0 +1,14 @@
+package main
+
+import (
+	"fmt"
+)
+
+var (
+	foo =  "misaligned"
+	bar =    "variables"
+)
+
+func main() {
+	fmt.Println("Hello world")
+}
diff --git a/testdata/multiline_comments.txt b/testdata/multiline_comments.txt
new file mode 100644
index 0000000..4cbf819
--- /dev/null
+++ b/testdata/multiline_comments.txt
@@ -0,0 +1,25 @@
+package main
+
+import (
+	"error"
+	"fmt"
+	// example comment
+	// comment continues
+	// and continues
+	"io"
+	// example comment
+	"log"
+
+	// go-groups comment
+	"github.com/indeedeng/go-groups"
+
+	// followup comment
+	"golang.org/x/net/http2"
+	"golang.org/x/net/http2/h2c"
+
+	"google.golang.org/grpc"
+)
+
+func main() {
+	fmt.Println("Hello world")
+}
diff --git a/testdata/multiline_comments_invalid.txt b/testdata/multiline_comments_invalid.txt
new file mode 100644
index 0000000..38abaef
--- /dev/null
+++ b/testdata/multiline_comments_invalid.txt
@@ -0,0 +1,23 @@
+package main
+
+import (
+	// example comment
+	// comment continues
+	// and continues
+	"io"
+	"fmt"
+	// example comment
+	"log"
+	"error"
+	// go-groups comment
+	"github.com/indeedeng/go-groups"
+	// followup comment
+
+	"golang.org/x/net/http2"
+	"golang.org/x/net/http2/h2c"
+	"google.golang.org/grpc"
+)
+
+func main() {
+	fmt.Println("Hello world")
+}
diff --git a/testdata/prefixed_groups.txt b/testdata/prefixed_groups.txt
new file mode 100644
index 0000000..1221162
--- /dev/null
+++ b/testdata/prefixed_groups.txt
@@ -0,0 +1,30 @@
+package foo
+
+import (
+	"fmt"
+	"os/user"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/pkg/errors"
+
+	"indeed.com/devops/libmarvin/spec"
+	"indeed.com/devops/marvlet/backend"
+	"indeed.com/devops/marvlet/backend/indeed"
+
+	"indeed.com/gophers/libarc"
+	"indeed.com/gophers/libops"
+	"indeed.com/gophers/rlog"
+
+	appsv1 "k8s.io/api/apps/v1"
+	apiv1 "k8s.io/api/core/v1"
+
+	"k8s.io/apimachinery/pkg/api/resource"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/apimachinery/pkg/util/intstr"
+
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/kubernetes/typed/apps/v1"
+)
diff --git a/testdata/prefixed_groups_invalid.txt b/testdata/prefixed_groups_invalid.txt
new file mode 100644
index 0000000..3d77632
--- /dev/null
+++ b/testdata/prefixed_groups_invalid.txt
@@ -0,0 +1,29 @@
+package foo
+
+import (
+	"fmt"
+	"os/user"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/pkg/errors"
+	"indeed.com/gophers/libarc"
+	"indeed.com/gophers/libops"
+	"indeed.com/gophers/rlog"
+
+	"indeed.com/devops/libmarvin/spec"
+	"indeed.com/devops/marvlet/backend"
+	"indeed.com/devops/marvlet/backend/indeed"
+
+	appsv1 "k8s.io/api/apps/v1"
+	apiv1 "k8s.io/api/core/v1"
+
+	"k8s.io/apimachinery/pkg/api/resource"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/apimachinery/pkg/util/intstr"
+
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/kubernetes/typed/apps/v1"
+)
diff --git a/testdata/sort_external_groups.txt b/testdata/sort_external_groups.txt
new file mode 100644
index 0000000..c37ca6c
--- /dev/null
+++ b/testdata/sort_external_groups.txt
@@ -0,0 +1,14 @@
+package foo
+
+import (
+    "net/http"
+    "testing"
+
+    "github.com/gin-gonic/gin"
+
+    "github.com/stretchr/testify/suite"
+
+    "indeed.com/devops/libmarvin/gin/ginhandler"
+    "indeed.com/devops/libmarvin/spec"
+    "indeed.com/devops/marvlet/api/v2"
+)
diff --git a/testdata/sort_external_groups_invalid.txt b/testdata/sort_external_groups_invalid.txt
new file mode 100644
index 0000000..777def7
--- /dev/null
+++ b/testdata/sort_external_groups_invalid.txt
@@ -0,0 +1,13 @@
+package foo
+
+import (
+    "net/http"
+    "testing"
+
+    "indeed.com/devops/libmarvin/gin/ginhandler"
+    "indeed.com/devops/libmarvin/spec"
+    "indeed.com/devops/marvlet/api/v2"
+
+    "github.com/gin-gonic/gin"
+    "github.com/stretchr/testify/suite"
+)
diff --git a/testdata/subdomain_imports.txt b/testdata/subdomain_imports.txt
new file mode 100644
index 0000000..8718422
--- /dev/null
+++ b/testdata/subdomain_imports.txt
@@ -0,0 +1,18 @@
+package foo
+
+import (
+	"context"
+	"io"
+	"net/http"
+	"strconv"
+	"strings"
+
+	"github.com/grpc-ecosystem/grpc-gateway/runtime"
+
+	"github.com/shoenig/petrify/v4"
+
+	"golang.org/x/net/http2"
+	"golang.org/x/net/http2/h2c"
+
+	"google.golang.org/grpc"
+)
diff --git a/testdata/subdomain_imports_invalid.txt b/testdata/subdomain_imports_invalid.txt
new file mode 100644
index 0000000..02b383e
--- /dev/null
+++ b/testdata/subdomain_imports_invalid.txt
@@ -0,0 +1,17 @@
+package foo
+
+import (
+	"context"
+	"io"
+	"net/http"
+	"strconv"
+	"strings"
+
+	"github.com/grpc-ecosystem/grpc-gateway/runtime"
+
+	"github.com/shoenig/petrify/v4"
+
+	"golang.org/x/net/http2"
+	"golang.org/x/net/http2/h2c"
+	"google.golang.org/grpc"
+)
diff --git a/testdata/valid_imports.txt b/testdata/valid_imports.txt
new file mode 100644
index 0000000..da6909f
--- /dev/null
+++ b/testdata/valid_imports.txt
@@ -0,0 +1,10 @@
+package foo
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"strconv"
+	"strings"
+)