add a --require option to specify directories which are required to be at the beginning of the path for any file that is going to be included in code coverage

make the --omit and --require options apply to code coverage generation as well as to reporting; This speeds up tests from 6 seconds to 1 second on my system, as well as making the resulting .coverage db include *only* the code that I care about, which helps with my code coverage progression/regression tool.

1 files changed, 14 insertions, 5 deletions

diff --git a/coverage/report.py b/coverage/report.py
index 5b66f99..e2a09fb 100644
--- a/coverage/report.py
+++ b/coverage/report.py
@@ -24,26 +24,35 @@ class Reporter(object):
         # classes.
         self.directory = None
 
-    def find_code_units(self, morfs, omit_prefixes):
+    def find_code_units(self, morfs, omit_prefixes, require_prefixes):
         """Find the code units we'll report on.
-
         `morfs` is a list of modules or filenames. `omit_prefixes` is a list
         of prefixes to leave out of the list.
 
+        `omit_prefixes` is a list of prefixes.  CodeUnits that match those prefixes
+        will be omitted from the list.
+        `require_prefixes` is a list of prefixes.  Only CodeUnits that match those prefixes
+        will be included in the list.
+        You are required to pass at most one of `omit_prefixes` and `require_prefixes`.
         """
         morfs = morfs or self.coverage.data.executed_files()
         self.code_units = code_unit_factory(
-                            morfs, self.coverage.file_locator, omit_prefixes)
+                            morfs, self.coverage.file_locator, omit_prefixes, require_prefixes)
         self.code_units.sort()
 
     def report_files(self, report_fn, morfs, directory=None,
-                        omit_prefixes=None):
+                        omit_prefixes=None, require_prefixes=None):
         """Run a reporting function on a number of morfs.
 
         `report_fn` is called for each relative morf in `morfs`.
 
+        `omit_prefixes` is a list of prefixes.  CodeUnits that match those prefixes
+        will be omitted from the list.
+        `require_prefixes` is a list of prefixes.  Only CodeUnits that match those prefixes
+        will be included in the list.
+        You are required to pass at most one of `omit_prefixes` and `require_prefixes`.
         """
-        self.find_code_units(morfs, omit_prefixes)
+        self.find_code_units(morfs, omit_prefixes, require_prefixes)
 
         if not self.code_units:
             raise CoverageException("No data to report.")