PYTHON-4526 DRIVERS_TOOLS needs to be set for encryption tests (mongodb#1723)

Author: ShaneHarvey

CONTRIBUTING.md

@@ -216,6 +216,9 @@ the pages will re-render and the browser will automatically refresh.
     `TEST_LOADBALANCER=1 tox -m test-eg`.
 
 ## Running Encryption Tests Locally
+- Clone `drivers-evergreen-tools`:
+  `git clone [email protected]:mongodb-labs/drivers-evergreen-tools.git`.
+- Run `export DRIVERS_TOOLS=$PWD/drivers-evergreen-tools`
 - Run `AWS_PROFILE=<profile> tox -m setup-encryption` after setting up your AWS profile with `aws configure sso`.
 - Run the tests with `TEST_ENCRYPTION=1 tox -e test-eg`.
 - When done, run `tox -m teardown-encryption` to clean up.

tox.ini

@@ -197,7 +197,7 @@ allowlist_externals =
     bash
 commands =
     bash .evergreen/setup-libmongocrypt.sh
-    bash {env:DRIVERS_TOOLS}/.evergreen/csfle/setup-secrets.sh
+    bash {env:DRIVERS_TOOLS:DRIVERS_TOOLS_var_undefined}/.evergreen/csfle/setup-secrets.sh
     bash {env:DRIVERS_TOOLS}/.evergreen/csfle/start-servers.sh
 
 [testenv:teardown-encryption]
@@ -208,5 +208,5 @@ allowlist_externals =
     bash
     rm
 commands =
-    bash {env:DRIVERS_TOOLS}/.evergreen/csfle/stop-servers.sh
+    bash {env:DRIVERS_TOOLS:DRIVERS_TOOLS_var_undefined}/.evergreen/csfle/stop-servers.sh
     rm -rf libmongocrypt/ libmongocrypt_git/ libmongocrypt.tar.gz mongocryptd.pid