Update README for how to set test configuration.

* Update instructions in README for how to run set configuration for
  running tests.
* Skip ingress-https, ingress-iap, and ingress-asm-multi-backendconfig
  tests if expected variables are not set.

.gitignore

@@ -4,4 +4,4 @@ asm/
 .crt
 .key
 .pem
-certs/
+certs/

test/README.md

@@ -26,12 +26,42 @@ Make sure you have valid credentials for accessing GCP:
 gcloud auth login
 ```
 
+Set the project property in the core section by running:
+```
+gcloud config set project PROJECT_ID
+```
+
+Install jq by running:
+```
+sudo apt-get install jq
+```
+
 Make sure you are at the root directory of the repository.
 
 ```
 cd gke-networking-recipes
 ```
 
+
+Make sure to set ZONE and REGION environment variables before running tests. Resources will be deployed to the specified region and/or zone.
+```
+export ZONE=zone
+export REGION=region
+```
+
+Tests for ingress-https, ingress-iap, and ingress-asm-multi-backendconfig will be skipped if the expected environment variables are not set.
+To run ingress-https and ingress-iap test, you need a special project($DNS_PROJECT) that has a configured domain name with Cloud DNS, and make sure the current service account has role/dns_admin access to that project. Then, create a public DNS zone and export its zone name and DNS name.
+```
+export DNS_PROJECT=dns-project \
+export DNS_ZONE=example-zone-name
+export DNS_NAME=myzone.example.com
+```
+
+To run ingress-iap and ingress_asm-multi-backendconfig test, you need to have a support email that follows the requirement described in Programmatic OAuth clients: https://cloud.google.com/iap/docs/programmatic-oauth-clients.
+```
+export SUPPORT_EMAIL=support-email
+```
+
 To run a specific test, run the setup.sh, run-test.sh, and cleanup.sh in order in the recipe directory.
 
 ```

test/recipe_test.go

@@ -47,6 +47,9 @@ func runRecipeTests(t *testing.T, parentPath string, fileNames []fs.DirEntry) {
 			if err := validateDir(path); err != nil {
 				t.Skipf("Skipping test %q: validateDir(%q) = %v", path, path, err)
 			}
+			if err := checkDependencies(path); err != nil {
+				t.Skipf("Skipping test %q: checkDependencies(%q) = %v", path, path, err)
+			}
 			runRecipeTest(t, path)
 		})
 	}
@@ -87,3 +90,27 @@ func validateDir(path string) error {
 	}
 	return nil
 }
+
+// checkDependencies checks if the dependencies are met for the given test.
+func checkDependencies(testName string) error {
+	if testName == "ingress/single-cluster/ingress-asm-multi-backendconfig" {
+		return checkEnvs("SUPPORT_EMAIL")
+	}
+	if testName == "ingress/single-cluster/ingress-https" {
+		return checkEnvs("DNS_PROJECT", "DNS_ZONE", "DNS_NAME")
+	}
+	if testName == "ingress/single-cluster/ingress-iap" {
+		return checkEnvs("DNS_PROJECT", "DNS_ZONE", "DNS_NAME", "SUPPORT_EMAIL")
+	}
+	return nil
+}
+
+// checkEnvs checks if all specified environment variables are set.
+func checkEnvs(envs ...string) error {
+	for _, env := range envs {
+		if _, found := os.LookupEnv(env); !found {
+			return fmt.Errorf("%q is not set. See test/README.md for more details", env)
+		}
+	}
+	return nil
+}