test: also test on versions of coverage

Author: nedbat

tests/banner.py

@@ -5,12 +5,14 @@
 
 import platform
 
+import coverage
 import django
 
 print(
-    "{} {}; Django {}".format(
+    "{} {}; Django {}; Coverage {}".format(
         platform.python_implementation(),
         platform.python_version(),
-        django.get_version()
+        django.get_version(),
+        coverage.__version__,
     )
 )

tox.ini

@@ -14,23 +14,26 @@
 
 [tox]
 envlist =
-    py37-django{111,22,32},
-    py38-django{22,32,40,41,tip},
-    py39-django{22,32,40,41,tip},
-    py310-django{32,40,41,tip},
-    py311-django{41,tip},
+    py37-django{111,22,32}-cov{5,6,tip},
+    py38-django{22,32,40,41,tip}-cov{5,6,tip},
+    py39-django{22,32,40,41,tip}-cov{5,6,tip},
+    py310-django{32,40,41,tip}-cov{5,6,tip},
+    py311-django{41,tip}-cov{6,tip},
     check,pkgcheck,doc
 
 [testenv]
 deps =
-    pytest
-    unittest-mixins==1.6
+    cov5: coverage>=5.0,<6.0
+    cov6: coverage>=6.0,<7.0
+    covtip: git+https://github.com/nedbat/coveragepy.git
     django111: Django>=1.11,<2.0
     django22: Django>=2.2,<3.0
     django32: Django>=3.2,<4.0
     django40: Django>=4.0,<4.1
     django41: Django>=4.1,<4.2
-    djangotip: https://github.com/django/django/archive/main.tar.gz
+    djangotip: git+https://github.com/django/django.git
+    pytest
+    unittest-mixins==1.6
 
 commands =
     python -c "import tests.banner"