test: deflake session test (#3864)

session/handler_test.go

@@ -187,7 +187,14 @@ func TestSessionWhoAmI(t *testing.T) {
 						if maxAge > 0 {
 							assert.Equal(t, fmt.Sprintf("%0.f", maxAge.Seconds()), res.Header.Get("Ory-Session-Cache-For"))
 						} else {
-							assert.Equal(t, fmt.Sprintf("%0.f", conf.SessionLifespan(ctx).Seconds()), res.Header.Get("Ory-Session-Cache-For"))
+							// parse int to string from Ory-Session-Cache-For
+							parsed, err := strconv.Atoi(res.Header.Get("Ory-Session-Cache-For"))
+							require.NoError(t, err)
+							lifespan := conf.SessionLifespan(ctx).Seconds()
+							// We need to account for the time it takes to make the request, as depending on the system it might take a few more ms which leads to the value being off by a second or more.
+							assert.Condition(t, func() bool {
+								return parsed > int(lifespan-5) && parsed <= int(lifespan)
+							}, "Expected the value of the Ory-Session-Cache-For header to be roughly around the configured lifespan. Got parsed: %d, lifespan: %d", parsed, int(lifespan))
 						}
 					} else {
 						assert.Empty(t, res.Header.Get("Ory-Session-Cache-For"))