Grand test fixup (#138)

* start fixing up tests

* fix up tests + automate with drone

* fiddle with linting

* messing about with drone.yml

* some more fiddling

* hmmm

* add cache

* add vendor directory

* verbose

* ci updates

* update some little things

* update sig

vendor/github.com/urfave/cli/v2/errors.go

@@ -0,0 +1,141 @@
+package cli
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"strings"
+)
+
+// OsExiter is the function used when the app exits. If not set defaults to os.Exit.
+var OsExiter = os.Exit
+
+// ErrWriter is used to write errors to the user. This can be anything
+// implementing the io.Writer interface and defaults to os.Stderr.
+var ErrWriter io.Writer = os.Stderr
+
+// MultiError is an error that wraps multiple errors.
+type MultiError interface {
+	error
+	Errors() []error
+}
+
+// newMultiError creates a new MultiError. Pass in one or more errors.
+func newMultiError(err ...error) MultiError {
+	ret := multiError(err)
+	return &ret
+}
+
+type multiError []error
+
+// Error implements the error interface.
+func (m *multiError) Error() string {
+	errs := make([]string, len(*m))
+	for i, err := range *m {
+		errs[i] = err.Error()
+	}
+
+	return strings.Join(errs, "\n")
+}
+
+// Errors returns a copy of the errors slice
+func (m *multiError) Errors() []error {
+	errs := make([]error, len(*m))
+	for _, err := range *m {
+		errs = append(errs, err)
+	}
+	return errs
+}
+
+// ErrorFormatter is the interface that will suitably format the error output
+type ErrorFormatter interface {
+	Format(s fmt.State, verb rune)
+}
+
+// ExitCoder is the interface checked by `App` and `Command` for a custom exit
+// code
+type ExitCoder interface {
+	error
+	ExitCode() int
+}
+
+type exitError struct {
+	exitCode int
+	message  interface{}
+}
+
+// NewExitError calls Exit to create a new ExitCoder.
+//
+// Deprecated: This function is a duplicate of Exit and will eventually be removed.
+func NewExitError(message interface{}, exitCode int) ExitCoder {
+	return Exit(message, exitCode)
+}
+
+// Exit wraps a message and exit code into an error, which by default is
+// handled with a call to os.Exit during default error handling.
+//
+// This is the simplest way to trigger a non-zero exit code for an App without
+// having to call os.Exit manually. During testing, this behavior can be avoided
+// by overiding the ExitErrHandler function on an App or the package-global
+// OsExiter function.
+func Exit(message interface{}, exitCode int) ExitCoder {
+	return &exitError{
+		message:  message,
+		exitCode: exitCode,
+	}
+}
+
+func (ee *exitError) Error() string {
+	return fmt.Sprintf("%v", ee.message)
+}
+
+func (ee *exitError) ExitCode() int {
+	return ee.exitCode
+}
+
+// HandleExitCoder handles errors implementing ExitCoder by printing their
+// message and calling OsExiter with the given exit code.
+//
+// If the given error instead implements MultiError, each error will be checked
+// for the ExitCoder interface, and OsExiter will be called with the last exit
+// code found, or exit code 1 if no ExitCoder is found.
+//
+// This function is the default error-handling behavior for an App.
+func HandleExitCoder(err error) {
+	if err == nil {
+		return
+	}
+
+	if exitErr, ok := err.(ExitCoder); ok {
+		if err.Error() != "" {
+			if _, ok := exitErr.(ErrorFormatter); ok {
+				_, _ = fmt.Fprintf(ErrWriter, "%+v\n", err)
+			} else {
+				_, _ = fmt.Fprintln(ErrWriter, err)
+			}
+		}
+		OsExiter(exitErr.ExitCode())
+		return
+	}
+
+	if multiErr, ok := err.(MultiError); ok {
+		code := handleMultiError(multiErr)
+		OsExiter(code)
+		return
+	}
+}
+
+func handleMultiError(multiErr MultiError) int {
+	code := 1
+	for _, merr := range multiErr.Errors() {
+		if multiErr2, ok := merr.(MultiError); ok {
+			code = handleMultiError(multiErr2)
+		} else if merr != nil {
+			fmt.Fprintln(ErrWriter, merr)
+			if exitErr, ok := merr.(ExitCoder); ok {
+				code = exitErr.ExitCode()
+			}
+		}
+	}
+	return code
+}