README
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metamorphic 
Documentation
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Overview ¶
Package metamorphic provides facilities for running metamorphic, property-based testing. By running logically equivalent operations with different conditions, metamorphic tests can identify bugs without requiring an oracle.
Index ¶
- func Generate[I any](n int, fn func() I) []I
- func Run[S any](t testing.TB, initial S, ops []Op[S])
- func Step[S any](l *Logger, s S, op Op[S])
- type ItemWeight
- type Logger
- func (l *Logger) Commentf(format string, args ...any)
- func (l *Logger) Error(err error)
- func (l *Logger) Errorf(format string, args ...any)
- func (l *Logger) FailNow()
- func (l *Logger) Fatal(args ...any)
- func (l *Logger) History() string
- func (l *Logger) Log(args ...any)
- func (l *Logger) Logf(format string, args ...interface{})
- func (l *Logger) Write(b []byte) (int, error)
- type Op
- type Weighted
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Generate ¶
Generate generates a sequence of n items, calling fn to produce each item. It's intended to be used with a function returned by (Weighted).Random or (Weighted).RandomDeck.
Types ¶
type ItemWeight ¶
ItemWeight holds an item and its corresponding weight.
type Logger ¶
type Logger struct {
// contains filtered or unexported fields
}
Logger logs test operation's outputs and errors, maintaining a cumulative history of the test. Logger may be used analogously to the standard library's testing.TB.
func RunInTandem ¶
RunInTandem takes n initial states and runs the provided set of operations against each incrementally. It fails the test as soon as any of the logs diverge.
func (*Logger) Commentf ¶
Commentf writes a comment to the log file. Commentf always appends a newline after the comment. Commentf may prepend a newline before the message if there isn't already one.
func (*Logger) FailNow ¶
func (l *Logger) FailNow()
FailNow marks the function as having failed and stops its execution by calling runtime.Goexit. FailNow is implemented by calling through to the underlying *testing.T's FailNow.
func (*Logger) Log ¶
Log formats its arguments using default formatting, analogous to Print, and records the text in the test's recorded history.
type Op ¶
type Op[S any] interface { fmt.Stringer // Run runs the operation, logging its outcome to Logger. Run(*Logger, S) }
Op represents a single operation within a metamorphic test.
type Weighted ¶
type Weighted[I any] []ItemWeight[I]
Weighted is a slice of items and their weights.
func (Weighted[I]) Random ¶
Random returns a function that returns one item at random, using the distribution indicated by item weights and the provided pseudorandom number generator for randomness.
func (Weighted[I]) RandomDeck ¶
RandomDeck returns a function that returns one item at random, using a deck-style distribution to ensure each item is returned with the desired frequency. Randomness is taken from the provided pseudorandom number generator.
Source Files
Directories