python 3.7 compat version of detecting console tty

Author: newbery

coverage/html.py

@@ -495,7 +495,7 @@ def index_file(self, first_html: str, final_html: str) -> None:
         index_file = os.path.join(self.directory, "index.html")
         write_html(index_file, html)
 
-        if os.isatty(sys.stdout.fileno()):
+        if sys.stdout.isatty():
             file_path = f"file://{os.path.abspath(index_file)}"
             print_path = f"\033]8;;{file_path}\a{index_file}\033]8;;\a"
         else:

coverage/report.py

@@ -59,7 +59,7 @@ def render_report(
     try:
         ret = reporter.report(morfs, outfile=outfile)
         if file_to_close is not None:
-            if os.isatty(sys.stdout.fileno()):
+            if sys.stdout.isatty():
                 file_path = f"file://{os.path.abspath(output_path)}"
                 print_path = f"\033]8;;{file_path}\a{output_path}\033]8;;\a"
             else: