Issue #19398: Extra slash no longer added to sys.path components in case of
empty compile-time PYTHONPATH components.  This fixes some tests in -S or -I
modes.
diff --git a/Lib/test/test_trace.py b/Lib/test/test_trace.py
index 2292ad6..4971fcd 100644
--- a/Lib/test/test_trace.py
+++ b/Lib/test/test_trace.py
@@ -293,11 +293,11 @@
         with captured_stdout() as stdout:
             self._coverage(tracer)
         stdout = stdout.getvalue()
-        self.assertTrue("pprint.py" in stdout)
-        self.assertTrue("case.py" in stdout)   # from unittest
+        self.assertIn("pprint.py", stdout)
+        self.assertIn("case.py", stdout)   # from unittest
         files = os.listdir(TESTFN)
-        self.assertTrue("pprint.cover" in files)
-        self.assertTrue("unittest.case.cover" in files)
+        self.assertIn("pprint.cover", files)
+        self.assertIn("unittest.case.cover", files)
 
     def test_coverage_ignore(self):
         # Ignore all files, nothing should be traced nor printed
diff --git a/Misc/NEWS b/Misc/NEWS
index aa00448..d136f2b 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,9 @@
 Core and Builtins
 -----------------
 
+- Issue #19398: Extra slash no longer added to sys.path components in case of
+  empty compile-time PYTHONPATH components.
+
 - Issue #21720: Improve exception message when the type of fromlist is unicode.
   fromlist parameter of __import__() only accepts str in Python 2 and this
   will help to identify the problem especially when the unicode_literals
diff --git a/Modules/getpath.c b/Modules/getpath.c
index 18b161c..c42ce31 100644
--- a/Modules/getpath.c
+++ b/Modules/getpath.c
@@ -597,7 +597,10 @@
 
             if (defpath[0] != SEP) {
                 strcat(buf, prefix);
-                strcat(buf, separator);
+                if (prefixsz >= 2 && prefix[prefixsz - 2] != SEP &&
+                    defpath[0] != (delim ? DELIM : L'\0')) {  /* not empty */
+                    strcat(buf, separator);
+                }
             }
 
             if (delim) {