From bbc054f546bbf22efdb4ed0b190600bd36512b6c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Chris=20Suszy=C5=84ski?= <ksuszyns@redhat.com>
Date: Mon, 24 Aug 2020 21:54:51 +0200
Subject: [PATCH] Docs for Eventing upgrade tests config overrides.

---
 test/upgrade/README.md        | 18 ++++++++++++++++++
 test/upgrade/prober/prober.go | 19 ++++++++++---------
 2 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/test/upgrade/README.md b/test/upgrade/README.md
index 10c477e1534..6f1619183b2 100644
--- a/test/upgrade/README.md
+++ b/test/upgrade/README.md
@@ -83,3 +83,21 @@ Diagram below describe the setup:
           +--------+       +---------+ |
            (default)        +----------+
 ```
+
+#### Probe test configuration
+
+Probe test behavior can be influenced from outside without modifying its source
+code. That can be beneficial if one would like to run upgrade tests in different
+context. One such example might be running Eventing upgrade tests in place that
+have Serving and Eventing both installed. In such environment one can set
+environment variable `E2E_UPGRADE_TESTS_SERVING_USE` to enable usage of ksvc
+forwarder (which is disabled by default):
+
+```
+$ export E2E_UPGRADE_TESTS_SERVING_USE=true
+```
+
+Any option, apart from namespace, in
+[`knative.dev/eventing/test/upgrade/prober.Config`](https://github.com/knative/eventing/blob/022e281/test/upgrade/prober/prober.go#L52-L63)
+struct can be influenced, by using `E2E_UPGRADE_TESTS_XXXXX` environmental
+variable prefix (using [kelseyhightower/envconfig](https://github.com/kelseyhightower/envconfig#usage) usage).
diff --git a/test/upgrade/prober/prober.go b/test/upgrade/prober/prober.go
index bf8179e1839..081448df3c6 100644
--- a/test/upgrade/prober/prober.go
+++ b/test/upgrade/prober/prober.go
@@ -64,19 +64,20 @@ type ServingConfig struct {
 }
 
 func NewConfig(namespace string) *Config {
-	servingConfig := ServingConfig{
-		Use:         false,
-		ScaleToZero: true,
-	}
-	err := envconfig.Process("e2e_upgrade_tests_serving", &servingConfig)
-	ensure.NoError(err)
-	return &Config{
-		Namespace:     namespace,
+	config := &Config{
+		Namespace:     "",
 		Interval:      Interval,
 		FinishedSleep: 5 * time.Second,
 		FailOnErrors:  true,
-		Serving:       servingConfig,
+		Serving: ServingConfig{
+			Use:         false,
+			ScaleToZero: true,
+		},
 	}
+	err := envconfig.Process("e2e_upgrade_tests", config)
+	ensure.NoError(err)
+	config.Namespace = namespace
+	return config
 }
 
 // RunEventProber starts a single Prober of the given domain.