--- a/test/test.cmake
+++ b/test/test.cmake
@@ -573,10 +573,14 @@ function(setup_aom_test_targets)
     if(((NOT MSVC) AND (NOT XCODE)) OR ENABLE_IDE_TEST_HOSTING)
 
       # Pick a reasonable number of targets (this controls parallelization).
-      processorcount(num_test_targets)
-      if(num_test_targets EQUAL 0) # Just default to 10 targets when there's no
-                                   # processor count available.
-        set(num_test_targets 10)
+      if(DEFINED ENV{LIBAOM_TEST_PROCS})
+          set(num_test_targets $ENV{LIBAOM_TEST_PROCS})
+      else()
+          processorcount(num_test_targets)
+          if(num_test_targets EQUAL 0) # Just default to 10 targets when there's no
+                                       # processor count available.
+          set(num_test_targets 10)
+          endif()
       endif()
 
       math(EXPR max_shard_index "${num_test_targets} - 1")