diff --git a/buildbot/master/files/config/factories.py b/buildbot/master/files/config/factories.py
index 439bc7ed..6c4e363d 100644
--- a/buildbot/master/files/config/factories.py
+++ b/buildbot/master/files/config/factories.py
@@ -115,19 +115,18 @@ def make_step(self, command):
 ])
 
 
-def make_cd_string(command):
-    return "cd /c/buildbot/slave/windows/build ; " + command
+def make_win_command(command):
+    cd_command = "cd /c/buildbot/slave/windows/build; " + command
+    return ["bash", "-l", "-c", cd_command]
 
 
 windows = ServoFactory([
     # TODO: convert this to use DynamicServoFactory
     # We need to run each command in a bash login shell, which breaks the
     # heuristics used by DynamicServoFactory.make_step
-    steps.Compile(command=["bash", "-l", "-c",
-                           make_cd_string("./mach build -d -v")],
+    steps.Compile(command=make_win_command("./mach build -d -v"),
                   env=envs.build_windows),
-    steps.Compile(command=["bash", "-l", "-c",
-                           make_cd_string("./mach test-unit")],
+    steps.Compile(command=make_win_command("./mach test-unit"),
                   env=envs.build_windows),
     # TODO: run lockfile_changed.sh and manifest_changed.sh scripts
 ])