Add input flag for reading from file instead of reading from pipe

Dockerfile

@@ -1,5 +1,6 @@
-#FROM alpine
-FROM golang:1.14-alpine
+ARG GO_VERSION=1.21.5
+
+FROM golang:${GO_VERSION}-alpine
 
 # installs GCC, libc-dev, etc
 RUN apk add build-base

Makefile

@@ -7,10 +7,16 @@ LIN_DIR := release_builds/linux-amd64/
 MAC_DIR := release_builds/darwin-amd64/
 WIN_DIR := release_builds/windows-amd64/
 
+GO_VERSION = 1.21.5
+
 .PHONY: help
 help: ## List of available commands
 	@awk 'BEGIN {FS = ":.*?## "} /^[a-zA-Z_-]+:.*?## / {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}' $(MAKEFILE_LIST)
 
+.PHONY: go-version
+go-version: ## Print Golang version
+	@echo "$(GO_VERSION)"
+
 genbuild:
 	go build
 
@@ -41,7 +47,7 @@ buildall: genbuild
 	echo "...Done!"
 
 dockertest: genbuild
-	docker build . -t go-test-report-test-runner:$(VERSION)
+	docker build --build-arg GO_VERSION=$(GO_VERSION) . -t go-test-report-test-runner:$(VERSION)
 
 .PHONY: lint
 lint: ## Run linter (https://github.com/golangci/golangci-lint/releases)

README.md

@@ -21,8 +21,9 @@
 The original version of the library has not been supported for more than three years.
 
 This version has some improvements:
-- support for the latest version of Golang
-- ability to split groups by package (instead of splitting by number of tests)
+- support latest version of Golang (using embed feature)
+- ability to split groups by package (instead of splitting by number of tests) (-p option)
+- ability to read test results from file (-i option)
 
 ## Installation
 
@@ -103,6 +104,7 @@ Available Commands:
 Flags:
   -g, --groupSize int   the number of tests per test group indicator (default 20)
   -h, --help            help for go-test-report
+  -i, --input string the JSON input file
   -o, --output string   the HTML output file (default "test_report.html")
   -s, --size string     the size (in pixels) of the clickable indicator for test result groups (default "24")
   -t, --title string    the title text shown in the test report (default "go-test-report")

main.go

@@ -84,6 +84,7 @@ type (
 		groupPackage bool
 		nosortFlag   bool
 		listFlag     string
+		inputFlag    string
 		outputFlag   string
 		verbose      bool
 	}
@@ -141,10 +142,19 @@ func initRootCommand() (*cobra.Command, *templateData, *cmdFlags) {
 			tmplData.sortTestsByName = !flags.nosortFlag
 			tmplData.ReportTitle = flags.titleFlag
 			tmplData.OutputFilename = flags.outputFlag
-			if err := checkIfStdinIsPiped(); err != nil {
-				return err
+			var stdin *os.File
+			if flags.inputFlag != "" {
+				file, err := os.Open(flags.inputFlag)
+				if err != nil {
+					return err
+				}
+				stdin = file
+			} else {
+				if err := checkIfStdinIsPiped(); err != nil {
+					return err
+				}
+				stdin = os.Stdin
 			}
-			stdin := os.Stdin
 			stdinScanner := bufio.NewScanner(stdin)
 			testReportHTMLTemplateFile, _ := os.Create(tmplData.OutputFilename)
 			reportFileWriter := bufio.NewWriter(testReportHTMLTemplateFile)
@@ -227,6 +237,11 @@ func initRootCommand() (*cobra.Command, *templateData, *cmdFlags) {
 		"l",
 		"",
 		"the JSON module list")
+	rootCmd.PersistentFlags().StringVarP(&flags.inputFlag,
+		"input",
+		"i",
+		"",
+		"the JSON input file")
 	rootCmd.PersistentFlags().StringVarP(&flags.outputFlag,
 		"output",
 		"o",