Displaying pip list command's packages and versions #5062

src/_pytest/terminal.py

@@ -9,6 +9,7 @@
 import argparse
 import collections
 import platform
+import subprocess
 import sys
 import time
 
@@ -574,6 +575,11 @@ def pytest_sessionstart(self, session):
         ):
             msg += " -- " + str(sys.executable)
         self.write_line(msg)
+        pipe = subprocess.Popen("pip list", shell=True, stdout=subprocess.PIPE).stdout
+        package_msg = pipe.read()
+        package_msg = package_msg[:-2]
+        if package_msg:
+            self.write_line(package_msg)
         lines = self.config.hook.pytest_report_header(
             config=self.config, startdir=self.startdir
         )

testing/test_terminal.py

@@ -278,6 +278,15 @@ def test_rewrite(self, testdir, monkeypatch):
         tr.rewrite("hey", erase=True)
         assert f.getvalue() == "hello" + "\r" + "hey" + (6 * " ")
 
+    def test_packages_display(self, testdir):
+        testdir.makepyfile(
+            """
+            def test_pass(num):
+                assert 1 == 1"""
+        )
+        result = testdir.runpytest()
+        result.stdout.fnmatch_lines(["*Package*", "*Version*"])
+
 
 class TestCollectonly(object):
     def test_collectonly_basic(self, testdir):