testscript: port "mv" and "! cmp" from upstream

testscript/cmd.go

@@ -35,15 +35,16 @@ var scriptCmds = map[string]func(*TestScript, bool, []string){
 	"exists":   (*TestScript).cmdExists,
 	"grep":     (*TestScript).cmdGrep,
 	"mkdir":    (*TestScript).cmdMkdir,
+	"mv":       (*TestScript).cmdMv,
 	"rm":       (*TestScript).cmdRm,
-	"unquote":  (*TestScript).cmdUnquote,
 	"skip":     (*TestScript).cmdSkip,
-	"stdin":    (*TestScript).cmdStdin,
 	"stderr":   (*TestScript).cmdStderr,
+	"stdin":    (*TestScript).cmdStdin,
 	"stdout":   (*TestScript).cmdStdout,
 	"stop":     (*TestScript).cmdStop,
 	"symlink":  (*TestScript).cmdSymlink,
 	"unix2dos": (*TestScript).cmdUNIX2DOS,
+	"unquote":  (*TestScript).cmdUnquote,
 	"wait":     (*TestScript).cmdWait,
 }
 
@@ -95,29 +96,22 @@ func (ts *TestScript) cmdChmod(neg bool, args []string) {
 
 // cmp compares two files.
 func (ts *TestScript) cmdCmp(neg bool, args []string) {
-	if neg {
-		// It would be strange to say "this file can have any content except this precise byte sequence".
-		ts.Fatalf("unsupported: ! cmp")
-	}
 	if len(args) != 2 {
 		ts.Fatalf("usage: cmp file1 file2")
 	}
 
-	ts.doCmdCmp(args, false)
+	ts.doCmdCmp(neg, args, false)
 }
 
 // cmpenv compares two files with environment variable substitution.
 func (ts *TestScript) cmdCmpenv(neg bool, args []string) {
-	if neg {
-		ts.Fatalf("unsupported: ! cmpenv")
-	}
 	if len(args) != 2 {
 		ts.Fatalf("usage: cmpenv file1 file2")
 	}
-	ts.doCmdCmp(args, true)
+	ts.doCmdCmp(neg, args, true)
 }
 
-func (ts *TestScript) doCmdCmp(args []string, env bool) {
+func (ts *TestScript) doCmdCmp(neg bool, args []string, env bool) {
 	name1, name2 := args[0], args[1]
 	text1 := ts.ReadFile(name1)
 
@@ -128,8 +122,15 @@ func (ts *TestScript) doCmdCmp(args []string, env bool) {
 	if env {
 		text2 = ts.expand(text2)
 	}
-	if text1 == text2 {
-		return
+	eq := text1 == text2
+	if neg {
+		if eq {
+			ts.Fatalf("%s and %s do not differ", name1, name2)
+		}
+		return // they differ, as expected
+	}
+	if eq {
+		return // they are equal, as expected
 	}
 	if ts.params.UpdateScripts && !env {
 		if scriptFile, ok := ts.scriptFiles[absName2]; ok {
@@ -324,6 +325,16 @@ func (ts *TestScript) cmdMkdir(neg bool, args []string) {
 	}
 }
 
+func (ts *TestScript) cmdMv(neg bool, args []string) {
+	if neg {
+		ts.Fatalf("unsupported: ! mv")
+	}
+	if len(args) != 2 {
+		ts.Fatalf("usage: mv old new")
+	}
+	ts.Check(os.Rename(ts.MkAbs(args[0]), ts.MkAbs(args[1])))
+}
+
 // unquote unquotes files.
 func (ts *TestScript) cmdUnquote(neg bool, args []string) {
 	if neg {

testscript/doc.go

@@ -129,14 +129,15 @@ The predefined commands are:
     Change the permissions of the files or directories named by the path arguments
     to the given octal mode (000 to 777).
 
-- cmp file1 file2
-  Check that the named files have the same content.
+  - [!] cmp file1 file2
+    Check that the named files have (or do not have) the same content.
     By convention, file1 is the actual data and file2 the expected data.
     File1 can be "stdout" or "stderr" to use the standard output or standard error
     from the most recent exec or wait command.
-  (If the files have differing content, the failure prints a diff.)
+    (If the files have differing content and the command is not negated,
+    the failure prints a diff.)
 
-- cmpenv file1 file2
+  - [!] cmpenv file1 file2
     Like cmp, but environment variables in file2 are substituted before the
     comparison. For example, $GOOS is replaced by the target GOOS.
 
@@ -179,27 +180,25 @@ The predefined commands are:
   - mkdir path...
     Create the listed directories, if they do not already exists.
 
-- unquote file...
-  Rewrite each file by replacing any leading ">" characters from
-  each line. This enables a file to contain substrings that look like
-  txtar file markers.
-  See also https://godoc.org/github.com/rogpeppe/go-internal/txtar#Unquote
+  - mv path1 path2
+    Rename path1 to path2. OS-specific restrictions may apply when path1 and path2
+    are in different directories.
 
   - rm file...
     Remove the listed files or directories.
 
   - skip [message]
     Mark the test skipped, including the message if given.
 
+  - [!] stderr [-count=N] pattern
+    Apply the grep command (see above) to the standard error
+    from the most recent exec or wait command.
+
   - stdin file
     Set the standard input for the next exec command to the contents of the given file.
     File can be "stdout" or "stderr" to use the standard output or standard error
     from the most recent exec or wait command.
 
-- [!] stderr [-count=N] pattern
-  Apply the grep command (see above) to the standard error
-  from the most recent exec or wait command.
-
   - [!] stdout [-count=N] pattern
     Apply the grep command (see above) to the standard output
     from the most recent exec or wait command.
@@ -210,6 +209,12 @@ The predefined commands are:
   - symlink file -> target
     Create file as a symlink to target. The -> (like in ls -l output) is required.
 
+  - unquote file...
+    Rewrite each file by replacing any leading ">" characters from
+    each line. This enables a file to contain substrings that look like
+    txtar file markers.
+    See also https://godoc.org/github.com/rogpeppe/go-internal/txtar#Unquote
+
   - wait [command]
     Wait for all 'exec' and 'go' commands started in the background (with the '&'
     token) to exit, and display success or failure status for them.

testscript/exe.go

@@ -122,7 +122,7 @@ func RunMain(m TestingM, commands map[string]func() int) (exitCode int) {
 			}
 			scriptCmds[name] = func(ts *TestScript, neg bool, args []string) {
 				if ts.params.RequireExplicitExec {
-					ts.Fatalf("use 'exec %s' rather than '%s' (because RequireExplicitExec is enabled)", args[0], args[0])
+					ts.Fatalf("use 'exec %s' rather than '%s' (because RequireExplicitExec is enabled)", name, name)
 				}
 				ts.cmdExec(neg, append([]string{name}, args...))
 			}

testscript/testdata/cpstdout.txt

@@ -4,7 +4,14 @@
 exec cat hello.text
 cp stdout got
 cmp got hello.text
+! cmp got different.text
+
+exists got
+mv got new
+! exists got
+cmp new hello.text
 
 -- hello.text --
 hello world
-
+-- different.text --
+goodbye

testscript/testdata/testscript_explicit_exec.txt

@@ -9,8 +9,8 @@ unquote scripts-explicit/testscript.txt
 testscript scripts-implicit
 testscript scripts-explicit
 
-! testscript -verbose -explicit-exec scripts-implicit
-testscript -verbose -explicit-exec scripts-explicit
+! testscript -explicit-exec scripts-implicit
+testscript -explicit-exec scripts-explicit
 
 -- scripts-implicit/testscript.txt --
 >fprintargs stdout right