diff --git a/lldb/packages/Python/lldbsuite/test/configuration.py b/lldb/packages/Python/lldbsuite/test/configuration.py
--- a/lldb/packages/Python/lldbsuite/test/configuration.py
+++ b/lldb/packages/Python/lldbsuite/test/configuration.py
@@ -103,6 +103,10 @@
 # because it doesn't work under a debugger
 testdirs = [lldbsuite.lldb_test_root]
 
+# The root of the test case tree (where the actual tests reside, not the test
+# infrastructure).
+test_src_root = lldbsuite.lldb_test_root
+
 # Separator string.
 separator = '-' * 70
 
diff --git a/lldb/packages/Python/lldbsuite/test/dotest.py b/lldb/packages/Python/lldbsuite/test/dotest.py
--- a/lldb/packages/Python/lldbsuite/test/dotest.py
+++ b/lldb/packages/Python/lldbsuite/test/dotest.py
@@ -467,7 +467,6 @@
         sys.exit(-1)
 
     os.environ["LLDB_TEST"] = scriptPath
-    os.environ["LLDB_TEST_SRC"] = lldbsuite.lldb_test_root
 
     # Set up the root build directory.
     if not configuration.test_build_dir:
diff --git a/lldb/packages/Python/lldbsuite/test/lldbtest.py b/lldb/packages/Python/lldbsuite/test/lldbtest.py
--- a/lldb/packages/Python/lldbsuite/test/lldbtest.py
+++ b/lldb/packages/Python/lldbsuite/test/lldbtest.py
@@ -496,7 +496,7 @@
             mydir = TestBase.compute_mydir(__file__)
         '''
         # /abs/path/to/packages/group/subdir/mytest.py -> group/subdir
-        rel_prefix = test_file[len(os.environ["LLDB_TEST_SRC"]) + 1:]
+        rel_prefix = test_file[len(configuration.test_src_root) + 1:]
         return os.path.dirname(rel_prefix)
 
     def TraceOn(self):
@@ -520,15 +520,11 @@
         # Save old working directory.
         cls.oldcwd = os.getcwd()
 
-        # Change current working directory if ${LLDB_TEST_SRC} is defined.
-        # See also dotest.py which sets up ${LLDB_TEST_SRC}.
-        if ("LLDB_TEST_SRC" in os.environ):
-            full_dir = os.path.join(os.environ["LLDB_TEST_SRC"],
-                                    cls.mydir)
-            if traceAlways:
-                print("Change dir to:", full_dir, file=sys.stderr)
-            os.chdir(full_dir)
-            lldb.SBReproducer.SetWorkingDirectory(full_dir)
+        full_dir = os.path.join(configuration.test_src_root, cls.mydir)
+        if traceAlways:
+            print("Change dir to:", full_dir, file=sys.stderr)
+        os.chdir(full_dir)
+        lldb.SBReproducer.SetWorkingDirectory(full_dir)
 
         # Set platform context.
         cls.platformContext = lldbplatformutil.createPlatformContext()
@@ -662,7 +658,7 @@
 
     def getSourceDir(self):
         """Return the full path to the current test."""
-        return os.path.join(os.environ["LLDB_TEST_SRC"], self.mydir)
+        return os.path.join(configuration.test_src_root, self.mydir)
 
     def getBuildDirBasename(self):
         return self.__class__.__module__ + "." + self.testMethodName
@@ -1095,7 +1091,7 @@
 
         <session-dir>/<arch>-<compiler>-<test-file>.<test-class>.<test-method>
         """
-        dname = os.path.join(os.environ["LLDB_TEST_SRC"],
+        dname = os.path.join(configuration.test_src_root,
                              os.environ["LLDB_SESSION_DIRNAME"])
         if not os.path.isdir(dname):
             os.mkdir(dname)
diff --git a/lldb/packages/Python/lldbsuite/test/plugins/builder_base.py b/lldb/packages/Python/lldbsuite/test/plugins/builder_base.py
--- a/lldb/packages/Python/lldbsuite/test/plugins/builder_base.py
+++ b/lldb/packages/Python/lldbsuite/test/plugins/builder_base.py
@@ -62,12 +62,11 @@
 
     # Construct the base make invocation.
     lldb_test = os.environ["LLDB_TEST"]
-    lldb_test_src = os.environ["LLDB_TEST_SRC"]
-    if not (lldb_test and lldb_test_src and configuration.test_build_dir and test_subdir and
+    if not (lldb_test and configuration.test_build_dir and test_subdir and
             test_name and (not os.path.isabs(test_subdir))):
         raise Exception("Could not derive test directories")
     build_dir = os.path.join(configuration.test_build_dir, test_subdir, test_name)
-    src_dir = os.path.join(lldb_test_src, test_subdir)
+    src_dir = os.path.join(configuration.test_src_root, test_subdir)
     # This is a bit of a hack to make inline testcases work.
     makefile = os.path.join(src_dir, "Makefile")
     if not os.path.isfile(makefile):