Add "test" command

  https://hadoop.apache.org/docs/stable/hadoop-project-dist/hadoop-common/FileSystemShell.html#test

Fixes #157

cmd/hdfs/main.go

@@ -32,6 +32,7 @@ Valid commands:
   cat SOURCE...
   head [-n LINES | -c BYTES] SOURCE...
   tail [-n LINES | -c BYTES] SOURCE...
+  test [-defsz] FILE...
   du [-sh] FILE...
   checksum FILE...
   get SOURCE [DEST]
@@ -57,6 +58,13 @@ Valid commands:
 	mkdirOpts = getopt.New()
 	mkdirp    = mkdirOpts.Bool('p')
 
+	testOpts = getopt.New()
+	teste    = testOpts.Bool('e')
+	testf    = testOpts.Bool('f')
+	testd    = testOpts.Bool('d')
+	testz    = testOpts.Bool('z')
+	tests    = testOpts.Bool('s')
+
 	touchOpts = getopt.New()
 	touchc    = touchOpts.Bool('c')
 
@@ -95,6 +103,7 @@ func init() {
 	duOpts.SetUsage(printHelp)
 	getmergeOpts.SetUsage(printHelp)
 	dfOpts.SetUsage(printHelp)
+	testOpts.SetUsage(printHelp)
 }
 
 func main() {
@@ -148,6 +157,9 @@ func main() {
 	case "df":
 		dfOpts.Parse(argv)
 		df(*dfh)
+	case "test":
+		testOpts.Parse(argv)
+		test(testOpts.Args(), *teste, *testf, *testd, *testz, *tests)
 	case "truncate":
 		truncate(argv[1:])
 	// it's a seeeeecret command

cmd/hdfs/test.go

@@ -0,0 +1,57 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"os"
+)
+
+type testFn func(fi os.FileInfo) bool
+
+func test(args []string, exists, file, dir, empty, nonempty bool) {
+	if len(args) == 0 {
+		fatalWithUsage()
+	}
+
+	numFlags := 0
+	for _, b := range []bool{exists, dir, file, nonempty, empty} {
+		if b {
+			numFlags += 1
+		}
+	}
+
+	if numFlags != 1 {
+		fatal("exactly one test flag must be specified")
+	}
+
+	var f func(fi os.FileInfo) bool
+	switch {
+	case exists:
+		f = func(fi os.FileInfo) bool { return fi != nil }
+	case dir:
+		f = func(fi os.FileInfo) bool { return fi.IsDir() }
+	case file:
+		f = func(fi os.FileInfo) bool { return !fi.IsDir() }
+	case nonempty:
+		f = func(fi os.FileInfo) bool { return fi.Size() != 0 }
+	case empty:
+		f = func(fi os.FileInfo) bool { return fi.Size() == 0 }
+	}
+
+	expanded, client, err := getClientAndExpandedPaths(args)
+	if err != nil {
+		fatal(err)
+	}
+
+	for _, p := range expanded {
+		fi, err := client.Stat(p)
+		if err != nil && !errors.Is(err, os.ErrNotExist) {
+			fmt.Fprintln(os.Stderr, err)
+			continue
+		}
+
+		if !f(fi) {
+			status = 1
+		}
+	}
+}

cmd/hdfs/test/test.bats

@@ -0,0 +1,131 @@
+#!/usr/bin/env bats
+
+load helper
+
+setup() {
+  $HDFS mkdir -p /_test_cmd/test/dir1
+  $HDFS mkdir -p /_test_cmd/test/dir2
+  $HDFS mkdir -p /_test_cmd/test/dir3
+  $HDFS put $ROOT_TEST_DIR/testdata/empty.txt /_test_cmd/test/empty.txt
+  $HDFS put $ROOT_TEST_DIR/testdata/foo.txt /_test_cmd/test/foo.txt
+  $HDFS put $ROOT_TEST_DIR/testdata/foo.txt /_test_cmd/test/dir1/foo1.txt
+}
+
+@test "exists for existent file" {
+  run $HDFS test -e /_test_cmd/test/foo.txt
+  assert_success
+}
+
+@test "exists for existent dir" {
+  run $HDFS test -e /_test_cmd/test/dir1
+  assert_success
+}
+
+@test "exists for non existent file" {
+  run $HDFS test -e /_test_cmd/test/bar.txt
+  assert_failure
+}
+
+@test "exists for non existent dir" {
+  run $HDFS test -e /_test_cmd/test/dir9
+  assert_failure
+}
+
+@test "isfile for existent file" {
+  run $HDFS test -f /_test_cmd/test/foo.txt
+  assert_success
+}
+
+@test "isfile for existent dir" {
+  run $HDFS test -f /_test_cmd/test/dir1
+  assert_failure
+}
+
+@test "isfile for non existent file" {
+  run $HDFS test -f /_test_cmd/test/bar.txt
+  assert_failure
+}
+
+@test "isfile for non existent dir" {
+  run $HDFS test -f /_test_cmd/test/dir9
+  assert_failure
+}
+
+@test "isdir for existent file" {
+  run $HDFS test -d /_test_cmd/test/foo.txt
+  assert_failure
+}
+
+@test "isdir for existent dir" {
+  run $HDFS test -d /_test_cmd/test/dir1
+  assert_success
+}
+
+@test "isdir for non existent file" {
+  run $HDFS test -d /_test_cmd/test/bar.txt
+  assert_failure
+}
+
+@test "isdir for non existent dir" {
+  run $HDFS test -d /_test_cmd/test/dir9
+  assert_failure
+}
+
+@test "isnonempty for existent empty file" {
+  run $HDFS test -s /_test_cmd/test/empty.txt
+  assert_failure
+}
+
+@test "isnonempty for existent non empty file" {
+  run $HDFS test -s /_test_cmd/test/foo.txt
+  assert_success
+}
+
+@test "isnonempty for existent dir" {
+  run $HDFS test -s /_test_cmd/test/dir1
+  assert_failure
+}
+
+@test "isnonempty for non existent file" {
+  run $HDFS test -s /_test_cmd/test/bar.txt
+  assert_failure
+}
+
+@test "isnonempty for non existent dir" {
+  run $HDFS test -s /_test_cmd/test/dir9
+  assert_failure
+}
+
+@test "isempty for existent empty file" {
+  run $HDFS test -z /_test_cmd/test/empty.txt
+  assert_success
+}
+
+@test "isempty for existent non empty file" {
+  run $HDFS test -z /_test_cmd/test/foo.txt
+  assert_failure
+}
+
+# TOOD: check this outcome is correct
+@test "isempty for existent dir" {
+  run $HDFS test -z /_test_cmd/test/dir1
+  assert_success
+}
+
+@test "isempty for non existent file" {
+  run $HDFS test -z /_test_cmd/test/bar.txt
+  assert_failure
+}
+
+@test "isempty for non existent dir" {
+  run $HDFS test -z /_test_cmd/test/dir9
+  assert_failure
+}
+
+teardown() {
+  $HDFS rm -r /_test_cmd/test
+}
+
+teardown() {
+  $HDFS rm -r /_test_cmd/test
+}