fix: --fail-under=100 could report 100 is less than 100.

Use the same rounding rules for the fail-under message that are used for totals
everywhere else, so that it won't say:

    total of 100 is less than fail-under=100

2 files changed, 28 insertions, 0 deletions

diff --git a/tests/test_process.py b/tests/test_process.py
index 9c695b2a..04a8a2d5 100644
--- a/tests/test_process.py
+++ b/tests/test_process.py
@@ -1249,6 +1249,22 @@ class FailUnderTest(CoverageTest):
         expected = "Coverage failure: total of 42.86 is less than fail-under=42.88"
         assert expected == self.last_line_squeezed(out)
 
+    def test_report_99p9_is_not_ok(self):
+        # A file with 99.99% coverage:
+        self.make_file("ninety_nine_plus.py", """\
+            a = 1
+            """ + """
+            b = 2
+            """ * 20000 + """
+            if a > 3:
+                c = 4
+            """)
+        self.run_command("coverage run --source=. ninety_nine_plus.py")
+        st, out = self.run_command_status("coverage report --fail-under=100")
+        assert st == 2
+        expected = "Coverage failure: total of 99 is less than fail-under=100"
+        assert expected == self.last_line_squeezed(out)
+
 
 class FailUnderNoFilesTest(CoverageTest):
     """Test that nothing to report results in an error exit status."""
diff --git a/tests/test_results.py b/tests/test_results.py
index 5811b0c2..fa239e92 100644
--- a/tests/test_results.py
+++ b/tests/test_results.py
@@ -68,6 +68,18 @@ class NumbersTest(CoverageTest):
         assert n10000.pc_covered_str == "0.0"
         Numbers.set_precision(0)
 
+    @pytest.mark.parametrize("prec, pc, res", [
+        (0, 47.87, "48"),
+        (1, 47.87, "47.9"),
+        (0, 99.995, "99"),
+        (2, 99.99995, "99.99"),
+    ])
+    def test_display_covered(self, prec, pc, res):
+        # Numbers._precision is a global, which is bad.
+        Numbers.set_precision(prec)
+        assert Numbers.display_covered(pc) == res
+        Numbers.set_precision(0)
+
     def test_covered_ratio(self):
         n = Numbers(n_files=1, n_statements=200, n_missing=47)
         assert n.ratio_covered == (153, 200)