move Func, BoolFunc, tests as they require go1.21

Commit 69bc3bd5b37fa90e994be9acecf7430269591713 added support for Func()
and BoolFunc() to match stdlib. However, the Func method was added in
[go1.16.0], and BoolFunc in [go1.21.0], so running the tests on older
versions of Go would fail;

    docker run -it --rm -v ./:/pflag -w /pflag golang:1.21 sh -c 'go test -v ./...'
    # github.com/spf13/pflag [github.com/spf13/pflag.test]
    ./bool_func_test.go:86:28: cannot use stdFSet (type *flag.FlagSet) as type BoolFuncFlagSet in argument to runCase:
        *flag.FlagSet does not implement BoolFuncFlagSet (missing BoolFunc method)
    ./bool_func_test.go:113:21: undefined: io.Discard
    ./bool_func_test.go:116:28: cannot use stdFSet (type *flag.FlagSet) as type BoolFuncFlagSet in argument to runCase:
        *flag.FlagSet does not implement BoolFuncFlagSet (missing BoolFunc method)
    ./bool_func_test.go:139:7: undefined: errors.Is
    ./func_test.go:92:28: cannot use stdFSet (type *flag.FlagSet) as type FuncFlagSet in argument to runCase:
        *flag.FlagSet does not implement FuncFlagSet (missing Func method)
    ./func_test.go:119:21: undefined: io.Discard
    ./func_test.go:122:28: cannot use stdFSet (type *flag.FlagSet) as type FuncFlagSet in argument to runCase:
        *flag.FlagSet does not implement FuncFlagSet (missing Func method)
    ./func_test.go:145:7: undefined: errors.Is
    ./func_test.go:145:7: too many errors
    FAIL	github.com/spf13/pflag [build failed]

This patch moves the tests to a separate file that is not built for older
versions of Go.

[go1.16.0]: https://pkg.go.dev/[email protected]#Func
[go1.21.0]: https://pkg.go.dev/[email protected]#BoolFunc

Signed-off-by: Sebastiaan van Stijn <[email protected]>

1 files changed, 0 insertions, 93 deletions

diff --git a/func_test.go b/func_test.go
index d492b48..4badf93 100644
--- a/func_test.go
+++ b/func_test.go
@@ -1,9 +1,6 @@
 package pflag
 
 import (
-	"errors"
-	"flag"
-	"io"
 	"strings"
 	"testing"
 )
@@ -62,96 +59,6 @@ func TestFuncP(t *testing.T) {
 	}
 }
 
-func TestFuncCompat(t *testing.T) {
-	// compare behavior with the stdlib 'flag' package
-	type FuncFlagSet interface {
-		Func(name string, usage string, fn func(string) error)
-		Parse([]string) error
-	}
-
-	unitTestErr := errors.New("unit test error")
-	runCase := func(f FuncFlagSet, name string, args []string) (values []string, err error) {
-		fn := func(s string) error {
-			values = append(values, s)
-			if s == "err" {
-				return unitTestErr
-			}
-			return nil
-		}
-		f.Func(name, "Callback function", fn)
-
-		err = f.Parse(args)
-		return values, err
-	}
-
-	t.Run("regular parsing", func(t *testing.T) {
-		flagName := "fnflag"
-		args := []string{"--fnflag=xx", "--fnflag", "yy", "--fnflag=zz"}
-
-		stdFSet := flag.NewFlagSet("std test", flag.ContinueOnError)
-		stdValues, err := runCase(stdFSet, flagName, args)
-		if err != nil {
-			t.Fatalf("std flag: expected no error, got %v", err)
-		}
-		expected := []string{"xx", "yy", "zz"}
-		if !cmpLists(expected, stdValues) {
-			t.Fatalf("std flag: expected %v, got %v", expected, stdValues)
-		}
-
-		fset := NewFlagSet("pflag test", ContinueOnError)
-		pflagValues, err := runCase(fset, flagName, args)
-		if err != nil {
-			t.Fatalf("pflag: expected no error, got %v", err)
-		}
-		if !cmpLists(stdValues, pflagValues) {
-			t.Fatalf("pflag: expected %v, got %v", stdValues, pflagValues)
-		}
-	})
-
-	t.Run("error triggered by callback", func(t *testing.T) {
-		flagName := "fnflag"
-		args := []string{"--fnflag", "before", "--fnflag", "err", "--fnflag", "after"}
-
-		// test behavior of standard flag.Fset with an error triggered by the callback:
-		// (note: as can be seen in 'runCase()', if the callback sees "err" as a value
-		//  for the flag, it will return an error)
-		stdFSet := flag.NewFlagSet("std test", flag.ContinueOnError)
-		stdFSet.SetOutput(io.Discard) // suppress output
-
-		// run test case with standard flag.Fset
-		stdValues, err := runCase(stdFSet, flagName, args)
-
-		// double check the standard behavior:
-		// - .Parse() should return an error, which contains the error message
-		if err == nil {
-			t.Fatalf("std flag: expected an error triggered by callback, got no error instead")
-		}
-		if !strings.HasSuffix(err.Error(), unitTestErr.Error()) {
-			t.Fatalf("std flag: expected unittest error, got unexpected error value: %T %v", err, err)
-		}
-		// - the function should have been called twice, with the first two values,
-		//   the final "=after" should not be recorded
-		expected := []string{"before", "err"}
-		if !cmpLists(expected, stdValues) {
-			t.Fatalf("std flag: expected %v, got %v", expected, stdValues)
-		}
-
-		// now run the test case on a pflag FlagSet:
-		fset := NewFlagSet("pflag test", ContinueOnError)
-		pflagValues, err := runCase(fset, flagName, args)
-
-		// check that there is a similar error (note: pflag will _wrap_ the error, while the stdlib
-		// currently keeps the original message but creates a flat errors.Error)
-		if !errors.Is(err, unitTestErr) {
-			t.Fatalf("pflag: got unexpected error value: %T %v", err, err)
-		}
-		// the callback should be called the same number of times, with the same values:
-		if !cmpLists(stdValues, pflagValues) {
-			t.Fatalf("pflag: expected %v, got %v", stdValues, pflagValues)
-		}
-	})
-}
-
 func TestFuncUsage(t *testing.T) {
 	t.Run("regular func flag", func(t *testing.T) {
 		// regular func flag: