Add Errorf (#14)
diff --git a/errors.go b/errors.go
index e7bc750..7ec1c5d 100644
--- a/errors.go
+++ b/errors.go
@@ -130,6 +130,19 @@
func (c cause) Cause() error { return c.cause }
func (c cause) Message() string { return c.message }
+// Errorf formats according to a format specifier and returns the string
+// as a value that satisfies error.
+func Errorf(format string, args ...interface{}) error {
+ pc, _, _, _ := runtime.Caller(1)
+ return struct {
+ error
+ location
+ }{
+ fmt.Errorf(format, args...),
+ location(pc),
+ }
+}
+
// Wrap returns an error annotating the cause with message.
// If cause is nil, Wrap returns nil.
func Wrap(cause error, message string) error {
diff --git a/errors_test.go b/errors_test.go
index c54bec1..4d0e669 100644
--- a/errors_test.go
+++ b/errors_test.go
@@ -170,3 +170,20 @@
}
}
}
+
+func TestErrorf(t *testing.T) {
+ tests := []struct {
+ err error
+ want string
+ }{
+ {Errorf("read error without format specifiers"), "read error without format specifiers"},
+ {Errorf("read error with %d format specifier", 1), "read error with 1 format specifier"},
+ }
+
+ for _, tt := range tests {
+ got := tt.err.Error()
+ if got != tt.want {
+ t.Errorf("Errorf(%v): got: %q, want %q", tt.err, got, tt.want)
+ }
+ }
+}
diff --git a/example_test.go b/example_test.go
index 088d009..c5f2023 100644
--- a/example_test.go
+++ b/example_test.go
@@ -62,3 +62,10 @@
// Output: oh noes #2: whoops
}
+
+func ExampleErrorf() {
+ err := errors.Errorf("whoops: %s", "foo")
+ errors.Fprint(os.Stdout, err)
+
+ // Output: github.com/pkg/errors/example_test.go:67: whoops: foo
+}
