adding cli tests using testscript - gives 97.7% (all but logfatal and…

… actual 1 line main)

README.md

@@ -32,3 +32,5 @@ REMOVED: gone1
 NEW: new1
 NEW: new2
 ```
+
+See also [delta.txtar](delta.txtar) for examples (tests)

delta.go

@@ -34,16 +34,16 @@ var (
 	shortV      string
 )
 
-func usage(msg string) {
+func usage(msg string, args ...any) {
 	_, _ = fmt.Fprintf(os.Stderr, "Fortio delta %s usage:\n\t%s [flags] fileA fileB\nflags:\n",
 		shortV,
 		os.Args[0])
 	flag.PrintDefaults()
-	_, _ = fmt.Fprintf(os.Stderr, "Command flags (-a and -b) are space separeted and the lines are passed as the last argument")
+	_, _ = fmt.Fprintf(os.Stderr, "Command flags (-a and -b) are space separeted and the lines are passed as the last argument\n")
 	if msg != "" {
-		fmt.Fprintln(os.Stderr, msg)
+		fmt.Fprintf(os.Stderr, msg, args...)
+		fmt.Fprintln(os.Stderr)
 	}
-	os.Exit(1)
 }
 
 func toMap(filename string) (map[string]bool, error) {
@@ -65,6 +65,7 @@ func toMap(filename string) (map[string]bool, error) {
 
 func removeCommon(a, b map[string]bool) {
 	if len(a) > len(b) {
+		log.LogVf("Swapping A and B iteration order as B is smaller")
 		a, b = b, a
 	}
 	for e := range a {
@@ -97,17 +98,23 @@ func runCmd(cmd0 string, args ...string) {
 }
 
 func main() {
+	os.Exit(Main())
+}
+
+func Main() int {
 	flag.CommandLine.Usage = func() { usage("") }
 	log.SetFlagDefaultsForClientTools()
 	sV, longV, fullV := version.FromBuildInfo()
 	shortV = sV
 	flag.Parse()
 	if *fullVersion {
 		fmt.Print(fullV)
-		os.Exit(0)
+		return 0
 	}
-	if len(flag.Args()) != 2 {
-		usage("Need 2 arguments (old and new files)")
+	numArgs := len(flag.Args())
+	if numArgs != 2 {
+		usage("Need 2 arguments (old and new files), got %d (%v)", numArgs, flag.Args())
+		return 1
 	}
 	cmdList := strings.Split(*aCmd, " ")
 	aCmd0 := cmdList[0]
@@ -126,11 +133,13 @@ func main() {
 	// read file content into map
 	aSet, err := toMap(flag.Arg(0))
 	if err != nil {
-		log.Fatalf("Error reading old file: %v", err)
+		log.Errf("Error reading file A: %v", err)
+		return 1
 	}
 	bSet, err := toMap(flag.Arg(1))
 	if err != nil {
-		log.Fatalf("Error reading new file: %v", err)
+		log.Errf("Error reading file B: %v", err)
+		return 1
 	}
 	// remove common entries
 	removeCommon(aSet, bSet)
@@ -150,4 +159,5 @@ func main() {
 			runCmd(bCmd0, bArgs...)
 		}
 	}
+	return 0
 }

delta.txtar

@@ -0,0 +1,66 @@
+# testscript framework tests for delta command line
+
+# Basic usage test
+! delta
+! stdout .
+stderr 'Need 2 arguments'
+
+# -version
+delta -version
+stdout 'path	github.com/fortio/delta'
+! stderr .
+
+# -foo (bad flag)
+! delta -foo
+! stdout .
+stderr 'flag provided but not defined: -foo'
+
+# non existent input file A
+! delta foo1 foo2
+stderr 'E Error reading file A: open foo1: no such file or directory'
+! stdout .
+
+# non existent input file B
+! delta oldFile foo2
+stderr 'E Error reading file B: open foo2: no such file or directory'
+! stdout .
+
+# positive test (includes order of A/B iteration swap)
+delta -loglevel verbose -b 'echo NEW:' -a 'echo REMOVED:' oldFile newFile
+cmp stdout expected1
+stderr 'Fortio delta.*started - will run "echo REMOVED:" on entries unique to oldFile, and "echo NEW:" on ones unique to newFile'
+stderr 'Swapping A and B iteration order as B is smaller'
+
+# swapping a and b test
+delta -loglevel verbose -a 'echo NEW:' -b 'echo REMOVED:'  newFile oldFile
+cmp stdout expected2
+! stderr 'Swapping A and B iteration order as B is smaller'
+
+-- expected1 --
+REMOVED: gone 2
+REMOVED: gone1
+REMOVED: goneA
+REMOVED: goneZ
+NEW: new1
+NEW: new2
+-- expected2 --
+NEW: new1
+NEW: new2
+REMOVED: gone 2
+REMOVED: gone1
+REMOVED: goneA
+REMOVED: goneZ
+-- oldFile --
+goneZ
+old1
+goneA
+old2
+gone1
+old3
+gone 2
+-- newFile --
+new1
+old1
+old2
+old3
+new2

delta_test.go

@@ -0,0 +1,18 @@
+package main
+
+import (
+	"os"
+	"testing"
+
+	"github.com/rogpeppe/go-internal/testscript"
+)
+
+func TestMain(m *testing.M) {
+	os.Exit(testscript.RunMain(m, map[string]func() int{
+		"delta": Main,
+	}))
+}
+
+func TestDelta(t *testing.T) {
+	testscript.Run(t, testscript.Params{Dir: "./"})
+}

go.mod

@@ -2,6 +2,12 @@ module github.com/fortio/delta
 
 go 1.18
 
-require fortio.org/fortio v1.38.4-cli1
+require (
+	fortio.org/fortio v1.38.4-cli1
+	github.com/rogpeppe/go-internal v1.9.0
+)
 
-require golang.org/x/exp v0.0.0-20221111204811-129d8d6c17ab // indirect
+require (
+	github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e // indirect
+	golang.org/x/exp v0.0.0-20221111204811-129d8d6c17ab // indirect
+)

go.sum

@@ -1,5 +1,9 @@
 fortio.org/assert v1.1.2 h1:t6WGDqPD5VFrUvx30U0+3mgXXcoPonrdKqt0vfJHn8E=
 fortio.org/fortio v1.38.4-cli1 h1:qGGkqmh1soBVCKG+LZc4l3F3BE4oHVow6AUslunmzGU=
 fortio.org/fortio v1.38.4-cli1/go.mod h1:4DhI17BkI3sU0DR4Z2HwochdpphTae+8NgZwWy6epRk=
+github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e h1:aoZm08cpOy4WuID//EZDgcC4zIxODThtZNPirFr42+A=
+github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
+github.com/rogpeppe/go-internal v1.9.0 h1:73kH8U+JUqXU8lRuOHeVHaa/SZPifC7BkcraZVejAe8=
+github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
 golang.org/x/exp v0.0.0-20221111204811-129d8d6c17ab h1:1S7USr8/C0Sgk4egxq4zZ07zYt2Xh1IiFp8hUMXH/us=
 golang.org/x/exp v0.0.0-20221111204811-129d8d6c17ab/go.mod h1:CxIveKay+FTh1D0yPZemJVgC/95VzuuOLq5Qi4xnoYc=