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package circuitbreaker_test
import (
"context"
"errors"
"fmt"
"path/filepath"
"runtime"
"testing"
"time"
"github.com/go-kit/kit/endpoint"
)
func testFailingEndpoint(
t *testing.T,
breaker endpoint.Middleware,
primeWith int,
shouldPass func(int) bool,
requestDelay time.Duration,
openCircuitError string,
) {
_, file, line, _ := runtime.Caller(1)
caller := fmt.Sprintf("%s:%d", filepath.Base(file), line)
// Create a mock endpoint and wrap it with the breaker.
m := mock{}
var e endpoint.Endpoint
e = m.endpoint
e = breaker(e)
// Prime the endpoint with successful requests.
for i := 0; i < primeWith; i++ {
if _, err := e(context.Background(), struct{}{}); err != nil {
t.Fatalf("%s: during priming, got error: %v", caller, err)
}
time.Sleep(requestDelay)
}
// Switch the endpoint to start throwing errors.
m.err = errors.New("tragedy+disaster")
m.through = 0
// The first several should be allowed through and yield our error.
for i := 0; shouldPass(i); i++ {
if _, err := e(context.Background(), struct{}{}); err != m.err {
t.Fatalf("%s: want %v, have %v", caller, m.err, err)
}
time.Sleep(requestDelay)
}
through := m.through
// But the rest should be blocked by an open circuit.
for i := 0; i < 10; i++ {
if _, err := e(context.Background(), struct{}{}); err.Error() != openCircuitError {
t.Fatalf("%s: want %q, have %q", caller, openCircuitError, err.Error())
}
time.Sleep(requestDelay)
}
// Make sure none of those got through.
if want, have := through, m.through; want != have {
t.Errorf("%s: want %d, have %d", caller, want, have)
}
}
type mock struct {
through int
err error
}
func (m *mock) endpoint(context.Context, interface{}) (interface{}, error) {
m.through++
return struct{}{}, m.err
}
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