Testing and clean up for data.py

2 files changed, 77 insertions, 12 deletions

diff --git a/coverage/data.py b/coverage/data.py
index 7dae25c7..19e00087 100644
--- a/coverage/data.py
+++ b/coverage/data.py
@@ -41,6 +41,7 @@ class CoverageData:
         self.suffix = suffix
 
     def _make_filename(self):
+        assert self.use_file
         if not self.filename:
             self.filename = os.environ.get(
                                     self.filename_env, self.filename_default)
@@ -62,9 +63,12 @@ class CoverageData:
             self.write_file(self.filename)
 
     def erase(self):
-        if self.filename and os.path.exists(self.filename):
-            os.remove(self.filename)
-
+        if self.use_file:
+            self._make_filename()
+            if self.filename and os.path.exists(self.filename):
+                os.remove(self.filename)
+        self.executed = {}
+        
     def write_file(self, filename):
         """Write the coverage data to `filename`."""
         f = open(filename, 'wb')
@@ -96,17 +100,14 @@ class CoverageData:
         """ Treat self.filename as a file prefix, and combine the data from all
             of the files starting with that prefix.
         """
+        self._make_filename()
         data_dir, local = os.path.split(self.filename)
         for f in os.listdir(data_dir or '.'):
             if f.startswith(local):
                 full_path = os.path.join(data_dir, f)
-                file_data = self._read_file(full_path)
-                self._combine_data(file_data)
-
-    def _combine_data(self, new_data):
-        """Combine the `new_data` into `executed`."""
-        for filename, file_data in new_data.items():
-            self.executed.setdefault(filename, {}).update(file_data)
+                new_data = self._read_file(full_path)
+                for filename, file_data in new_data.items():
+                    self.executed.setdefault(filename, {}).update(file_data)
 
     def add_line_data(self, data_points):
         """Add executed line data.
diff --git a/test/test_data.py b/test/test_data.py
index 6e3d13f0..04dd9f28 100644
--- a/test/test_data.py
+++ b/test/test_data.py
@@ -3,8 +3,72 @@
 from coverage.data import CoverageData
 from coveragetest import CoverageTest
 
+try:
+    set()
+except:
+    from sets import Set as set
+
+DATA_1 = [ ('a.py',1), ('a.py',2), ('b.py',3) ]
+SUMMARY_1 = { 'a.py':2, 'b.py':1 }
+EXECED_FILES_1 = [ 'a.py', 'b.py' ]
+
+DATA_2 = [ ('a.py',1), ('a.py',5), ('c.py',17) ]
+SUMMARY_1_2 = { 'a.py':3, 'b.py':1, 'c.py':1 }
+EXECED_FILES_1_2 = [ 'a.py', 'b.py', 'c.py' ]
+
 class DataTest(CoverageTest):
-    def test_reading(self):
+    
+    def assert_summary(self, covdata, summary):
+        self.assertEqual(covdata.summary(), summary)
+        
+    def assert_executed_files(self, covdata, execed):
+        e1 = set(covdata.executed_files())
+        e2 = set(execed)
+        self.assertEqual(e1, e2)
+    
+    def test_reading_empty(self):
         covdata = CoverageData()
         covdata.read()
-        self.assertEqual(covdata.summary(), {})
+        self.assert_summary(covdata, {})
+
+    def test_adding_data(self):
+        covdata = CoverageData()
+        covdata.add_line_data(DATA_1)
+        self.assert_summary(covdata, SUMMARY_1)
+        self.assert_executed_files(covdata, EXECED_FILES_1)
+        
+    def test_writing_and_reading(self):
+        covdata1 = CoverageData()
+        covdata1.add_line_data(DATA_1)
+        covdata1.write()
+        
+        covdata2 = CoverageData()
+        covdata2.read()
+        self.assert_summary(covdata2, SUMMARY_1)
+
+    def test_combining(self):
+        covdata1 = CoverageData()
+        covdata1.set_suffix('1')
+        covdata1.add_line_data(DATA_1)
+        covdata1.write()
+        
+        covdata2 = CoverageData()
+        covdata2.set_suffix('2')
+        covdata2.add_line_data(DATA_2)
+        covdata2.write()
+        
+        covdata3 = CoverageData()
+        covdata3.combine_parallel_data()
+        self.assert_summary(covdata3, SUMMARY_1_2)
+        self.assert_executed_files(covdata3, EXECED_FILES_1_2)
+
+    def test_erasing(self):
+        covdata1 = CoverageData()
+        covdata1.add_line_data(DATA_1)
+        covdata1.write()
+        covdata1.erase()
+        self.assert_summary(covdata1, {})
+        
+        covdata2 = CoverageData()
+        covdata2.read()
+        self.assert_summary(covdata2, {})