Label HTTP metrics with the chi route pattern (closes #254)

internal/middleware/export_test.go

@@ -4,8 +4,28 @@ import (
 	"context"
 	"net/http"
 	"time"
+
+	httpmetrics "github.com/slok/go-http-metrics/metrics"
 )
 
+// MetricsMiddlewareForTest builds the metrics recording middleware
+// against a caller-supplied recorder, so a test can gather from its
+// own Prometheus registry rather than the process-wide default one
+// that Middleware.Metrics uses.
+func MetricsMiddlewareForTest(
+	rec httpmetrics.Recorder,
+) func(http.Handler) http.Handler {
+	return metricsMiddleware(rec)
+}
+
+// UnmatchedRouteConst exposes the sentinel that stands in for a
+// request matching no route pattern.
+const UnmatchedRouteConst = unmatchedRoute
+
+// InflightHandlerConst exposes the fixed handler label on the
+// inflight gauge.
+const InflightHandlerConst = inflightHandler
+
 // NewLoggingResponseWriterForTest wraps newLoggingResponseWriter
 // for use in external test packages.
 func NewLoggingResponseWriterForTest(