Add CHANGELOG entry

Fixes #3045.

CHANGELOG.md

@@ -7,6 +7,7 @@ CHANGELOG
 
 - Fix a crash when using StackReference from the `1.0.0-beta.3` version of
   `@pulumi/pulumi` and `1.0.0-beta.2` or earlier of the CLI.
+- Deprecate `PULUMI_TEST_MODE`. See [#3045](https://github.com/pulumi/pulumi/issues/3045) for details.
 
 ## 1.0.0-beta.3 (2019-08-21)
 

sdk/nodejs/runtime/settings.ts

@@ -71,7 +71,12 @@ export function _setTestModeEnabled(val: boolean) {
  * Returns true if test mode is enabled (PULUMI_TEST_MODE).
  */
 export function isTestModeEnabled(): boolean {
-    return options.testModeEnabled === true;
+    if (options.testModeEnabled === true) {
+        log.warn("PULUMI_TEST_MODE is deprecated, and will be removed soon; " +
+            "please see https://github.com/pulumi/pulumi/issues/3045 for details");
+        return true;
+    }
+    return false;
 }
 
 /**

sdk/python/lib/pulumi/runtime/settings.py

@@ -21,6 +21,7 @@ import sys
 from typing import Optional, Awaitable, TYPE_CHECKING
 
 import grpc
+from ..log import warn
 from ..runtime.proto import engine_pb2_grpc, resource_pb2, resource_pb2_grpc
 from ..errors import RunError
 
@@ -99,7 +100,11 @@ def is_test_mode_enabled() -> bool:
     """
     Returns true if test mode is enabled (PULUMI_TEST_MODE).
     """
-    return bool(SETTINGS.test_mode_enabled)
+    test_mode = bool(SETTINGS.test_mode_enabled)
+    if test_mode:
+        warn('PULUMI_TEST_MODE is deprecated, and will be removed soon; '+
+             'please see https://github.com/pulumi/pulumi/issues/3045 for details')
+    return test_mode
 
 
 def _set_test_mode_enabled(v: Optional[bool]):