Revert "Make detection for test-binary more universal (#2173)" (#2235)

This reverts commit d1e9d85.

Some programs set os.Args in their unit tests and this change would
break those tests.

Ref: #2173 (comment)

command.go

@@ -23,6 +23,7 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"path/filepath"
 	"sort"
 	"strings"
 
@@ -1100,11 +1101,8 @@ func (c *Command) ExecuteC() (cmd *Command, err error) {
 
 	args := c.args
 
-	// If running unit tests, we don't want to take the os.Args, see #155 and #2173.
-	// For example, the following would fail:
-	//   go test -c -o foo.test
-	//   ./foo.test -test.run TestNoArgs
-	if c.args == nil && !isTesting() {
+	// Workaround FAIL with "go test -v" or "cobra.test -test.v", see #155
+	if c.args == nil && filepath.Base(os.Args[0]) != "cobra.test" {
 		args = os.Args[1:]
 	}
 

command_test.go

@@ -2921,16 +2921,3 @@ func TestUnknownFlagShouldReturnSameErrorRegardlessOfArgPosition(t *testing.T) {
 		})
 	}
 }
-
-// This tests verifies that when running unit tests, os.Args are not used.
-// This is because we don't want to process any arguments that are provided
-// by "go test"; instead, unit tests must set the arguments they need using
-// rootCmd.SetArgs().
-func TestNoOSArgsWhenTesting(t *testing.T) {
-	root := &Command{Use: "root", Run: emptyRun}
-	os.Args = append(os.Args, "--unknown")
-
-	if _, err := root.ExecuteC(); err != nil {
-		t.Errorf("error: %v", err)
-	}
-}