Put back an always-on indication of the tracer available

2 files changed, 15 insertions, 3 deletions

diff --git a/coverage/control.py b/coverage/control.py
index 580fc9da..c4022f1f 100644
--- a/coverage/control.py
+++ b/coverage/control.py
@@ -13,7 +13,7 @@ import time
 from coverage import env
 from coverage.annotate import AnnotateReporter
 from coverage.backward import string_class, iitems
-from coverage.collector import Collector
+from coverage.collector import Collector, CTracer
 from coverage.config import read_coverage_config
 from coverage.data import CoverageData, combine_parallel_data
 from coverage.debug import DebugControl, write_formatted_info
@@ -836,6 +836,7 @@ class Coverage(object):
             ('version', covmod.__version__),
             ('coverage', covmod.__file__),
             ('tracer', self._collector.tracer_name() if self._collector else "-none-"),
+            ('CTracer', 'available' if CTracer else "unavailable"),
             ('plugins.file_tracers', plugin_info(self._plugins.file_tracers)),
             ('plugins.configurers', plugin_info(self._plugins.configurers)),
             ('configs_attempted', self.config.attempted_config_files),
diff --git a/tests/test_debug.py b/tests/test_debug.py
index 26ddc0df..284d9567 100644
--- a/tests/test_debug.py
+++ b/tests/test_debug.py
@@ -10,9 +10,10 @@ import pytest
 import coverage
 from coverage.backward import StringIO
 from coverage.debug import filter_text, info_formatter, info_header, short_id, short_stack
+from coverage.env import C_TRACER
 
 from tests.coveragetest import CoverageTest
-from tests.helpers import re_lines
+from tests.helpers import re_line, re_lines
 
 
 class InfoFormatterTest(CoverageTest):
@@ -160,7 +161,8 @@ class DebugTraceTest(CoverageTest):
             label_pat = r"^\s*%s: " % label
             self.assertEqual(
                 len(re_lines(out_lines, label_pat).splitlines()),
-                1
+                1,
+                msg="Incorrect lines for %r" % label,
             )
 
     def test_debug_sys(self):
@@ -179,6 +181,15 @@ class DebugTraceTest(CoverageTest):
                 msg="Incorrect lines for %r" % label,
             )
 
+    def test_debug_sys_ctracer(self):
+        out_lines = self.f1_debug_output(["sys"])
+        tracer_line = re_line(out_lines, r"CTracer:").strip()
+        if C_TRACER:
+            expected = "CTracer: available"
+        else:
+            expected = "CTracer: unavailable"
+        self.assertEqual(tracer_line, expected)
+
 
 def f_one(*args, **kwargs):
     """First of the chain of functions for testing `short_stack`."""