check_coverage: Truncate long floats

scripts/dev/check_coverage.py

@@ -239,7 +239,7 @@ def check(fileobj, perfect_files):
         is_bad = line_cov < 100 or branch_cov < 100
 
         if filename in perfect_src_files and is_bad:
-            text = "{} has {}% line and {}% branch coverage!".format(
+            text = "{} has {:.2f}% line and {:.2f}% branch coverage!".format(
                 filename, line_cov, branch_cov)
             messages.append(Message(MsgType.insufficent_coverage, filename,
                                     text))

tests/unit/scripts/test_check_coverage.py

@@ -131,7 +131,36 @@ def test_untested(covtest):
     expected = check_coverage.Message(
         check_coverage.MsgType.insufficent_coverage,
         'module.py',
-        'module.py has 75.0% line and 100.0% branch coverage!')
+        'module.py has 75.00% line and 100.00% branch coverage!')
+    assert covtest.check() == [expected]
+
+
+def test_untested_floats(covtest):
+    """Make sure we don't report 58.330000000000005% coverage."""
+    covtest.makefile("""
+        def func():
+            pass
+
+        def untested():
+            pass
+
+        def untested2():
+            pass
+
+        def untested3():
+            pass
+
+        def untested4():
+            pass
+
+        def untested5():
+            pass
+    """)
+    covtest.run()
+    expected = check_coverage.Message(
+        check_coverage.MsgType.insufficent_coverage,
+        'module.py',
+        'module.py has 58.33% line and 100.00% branch coverage!')
     assert covtest.check() == [expected]
 
 
@@ -150,7 +179,7 @@ def test_untested_branches(covtest):
     expected = check_coverage.Message(
         check_coverage.MsgType.insufficent_coverage,
         'module.py',
-        'module.py has 100.0% line and 50.0% branch coverage!')
+        'module.py has 100.00% line and 50.00% branch coverage!')
     assert covtest.check() == [expected]