[llvm][llvm-lit] Add a base class for reports that are written to files

This is to later allow me to handle the choosing of the filename
in one place, so that we can write unique files across multiple
runs.

Author: DavidSpickett

llvm/utils/lit/lit/reports.py

@@ -1,3 +1,4 @@
+import abc
 import base64
 import datetime
 import itertools
@@ -14,11 +15,22 @@ def by_suite_and_test_path(test):
     return (test.suite.name, id(test.suite), test.path_in_suite)
 
 
-class JsonReport(object):
+class Report(object):
     def __init__(self, output_file):
         self.output_file = output_file
 
     def write_results(self, tests, elapsed):
+        with open(self.output_file, "w") as file:
+            self._write_results_to_file(tests, elapsed, file)
+
+    @abc.abstractmethod
+    def _write_results_to_file(self, tests, elapsed, file):
+        """Write test results to the file object "file"."""
+        pass
+
+
+class JsonReport(Report):
+    def _write_results_to_file(self, tests, elapsed, file):
         unexecuted_codes = {lit.Test.EXCLUDED, lit.Test.SKIPPED}
         tests = [t for t in tests if t.result.code not in unexecuted_codes]
         # Construct the data we will write.
@@ -67,9 +79,8 @@ def write_results(self, tests, elapsed):
 
             tests_data.append(test_data)
 
-        with open(self.output_file, "w") as file:
-            json.dump(data, file, indent=2, sort_keys=True)
-            file.write("\n")
+        json.dump(data, file, indent=2, sort_keys=True)
+        file.write("\n")
 
 
 _invalid_xml_chars_dict = {
@@ -88,21 +99,18 @@ def remove_invalid_xml_chars(s):
     return s.translate(_invalid_xml_chars_dict)
 
 
-class XunitReport(object):
-    def __init__(self, output_file):
-        self.output_file = output_file
-        self.skipped_codes = {lit.Test.EXCLUDED, lit.Test.SKIPPED, lit.Test.UNSUPPORTED}
+class XunitReport(Report):
+    skipped_codes = {lit.Test.EXCLUDED, lit.Test.SKIPPED, lit.Test.UNSUPPORTED}
 
-    def write_results(self, tests, elapsed):
+    def _write_results_to_file(self, tests, elapsed, file):
         tests.sort(key=by_suite_and_test_path)
         tests_by_suite = itertools.groupby(tests, lambda t: t.suite)
 
-        with open(self.output_file, "w") as file:
-            file.write('<?xml version="1.0" encoding="UTF-8"?>\n')
-            file.write('<testsuites time="{time:.2f}">\n'.format(time=elapsed))
-            for suite, test_iter in tests_by_suite:
-                self._write_testsuite(file, suite, list(test_iter))
-            file.write("</testsuites>\n")
+        file.write('<?xml version="1.0" encoding="UTF-8"?>\n')
+        file.write('<testsuites time="{time:.2f}">\n'.format(time=elapsed))
+        for suite, test_iter in tests_by_suite:
+            self._write_testsuite(file, suite, list(test_iter))
+        file.write("</testsuites>\n")
 
     def _write_testsuite(self, file, suite, tests):
         skipped = 0
@@ -206,11 +214,8 @@ def gen_resultdb_test_entry(
     return test_data
 
 
-class ResultDBReport(object):
-    def __init__(self, output_file):
-        self.output_file = output_file
-
-    def write_results(self, tests, elapsed):
+class ResultDBReport(Report):
+    def _write_results_to_file(self, tests, elapsed, file):
         unexecuted_codes = {lit.Test.EXCLUDED, lit.Test.SKIPPED}
         tests = [t for t in tests if t.result.code not in unexecuted_codes]
         data = {}
@@ -249,17 +254,14 @@ def write_results(self, tests, elapsed):
                         )
                     )
 
-        with open(self.output_file, "w") as file:
-            json.dump(data, file, indent=2, sort_keys=True)
-            file.write("\n")
+        json.dump(data, file, indent=2, sort_keys=True)
+        file.write("\n")
 
 
-class TimeTraceReport(object):
-    def __init__(self, output_file):
-        self.output_file = output_file
-        self.skipped_codes = {lit.Test.EXCLUDED, lit.Test.SKIPPED, lit.Test.UNSUPPORTED}
+class TimeTraceReport(Report):
+    skipped_codes = {lit.Test.EXCLUDED, lit.Test.SKIPPED, lit.Test.UNSUPPORTED}
 
-    def write_results(self, tests, elapsed):
+    def _write_results_to_file(self, tests, elapsed, file):
         # Find when first test started so we can make start times relative.
         first_start_time = min([t.result.start for t in tests])
         events = [
@@ -270,8 +272,7 @@ def write_results(self, tests, elapsed):
 
         json_data = {"traceEvents": events}
 
-        with open(self.output_file, "w") as time_trace_file:
-            json.dump(json_data, time_trace_file, indent=2, sort_keys=True)
+        json.dump(json_data, time_trace_file, indent=2, sort_keys=True)
 
     def _get_test_event(self, test, first_start_time):
         test_name = test.getFullName()