Making CallStack immutable, so it can be hashable

appengine/findit/crash/test/stacktrace_test.py

Index: appengine/findit/crash/test/stacktrace_test.py
diff --git a/appengine/findit/crash/test/stacktrace_test.py b/appengine/findit/crash/test/stacktrace_test.py
index f0a5ace6fa66b612615efa5205101f5f3da021bb..56f998f76b426eb88772b807413cd0bb86e6a881 100644
--- a/appengine/findit/crash/test/stacktrace_test.py
+++ b/appengine/findit/crash/test/stacktrace_test.py
@@ -3,8 +3,8 @@
 # found in the LICENSE file.
 
 from common.dependency import Dependency
-from crash.stacktrace import StackFrame
 from crash.stacktrace import CallStack
+from crash.stacktrace import StackFrame
 from crash.stacktrace import Stacktrace
 from crash.test.stacktrace_test_suite import StacktraceTestSuite
 from crash.type_enums import CallStackFormatType
@@ -12,6 +12,30 @@ from crash.type_enums import CallStackLanguageType
 
 class CallStackTest(StacktraceTestSuite):
 
+  def testCallStackBool(self):
+    self.assertFalse(CallStack(0))
+    frame = StackFrame(0, 'src/', 'func', 'f.cc', 'src/f.cc', [])
+    self.assertTrue(CallStack(0, frame_list=[frame]))
+
+  def testCallStackSliceFrames(self):
+    frames = [
+        StackFrame(0, 'src/', 'func0', 'file0.cc', 'src/file0.cc', [32]),
+        StackFrame(1, 'src/', 'func1', 'file1.cc', 'src/file1.cc', [53]),
+        StackFrame(2, 'src/', 'func2', 'file2.cc', 'src/file2.cc', [3])]
+
+    self._VerifyTwoCallStacksEqual(
+        CallStack(0, frame_list=frames[2:2]),
+        CallStack(0, frame_list=frames).SliceFrames(2, 2))
+    self._VerifyTwoCallStacksEqual(
+        CallStack(0, frame_list=frames[:2]),
+        CallStack(0, frame_list=frames).SliceFrames(None, 2))
+    self._VerifyTwoCallStacksEqual(
+        CallStack(0, frame_list=frames[2:]),
+        CallStack(0, frame_list=frames).SliceFrames(2, None))
+    self._VerifyTwoCallStacksEqual(
+        CallStack(0, frame_list=frames[:]),
+        CallStack(0, frame_list=frames).SliceFrames(None, None))
+
   def testStackFrameToString(self):
     self.assertEqual(
         StackFrame(0, 'src/', 'func', 'f.cc', 'src/f.cc', []).ToString(),
@@ -33,68 +57,68 @@ class CallStackTest(StacktraceTestSuite):
     frame = frame._replace(crashed_line_numbers = [9, 10])
     self.assertEqual(frame.BlameUrl('1'), 'https://repo_url/+blame/1/f.cc#9')
 
-  def testFrameListInitCallStack(self):
-    stack = CallStack(0)
-    stack.extend([StackFrame(0, 'src/', '', 'func', 'f.cc', [2])])
-
-    copy_stack = CallStack(stack.priority, frame_list=stack)
-    self._VerifyTwoCallStacksEqual(copy_stack, stack)
-
-  def testParseLineForJavaCallstackFormat(self):
-    stack = CallStack(0, CallStackFormatType.JAVA)
+  def testCallStackConstructorIsLanguageJavaIfFormatJava(self):
+    self.assertEqual(
+        CallStack(0, format_type = CallStackFormatType.JAVA).language_type,
+        CallStackLanguageType.JAVA)
 
-    stack.ParseLine('dummy line', {})
-    self.assertEqual(stack, [])
+  def testParseStackFrameForJavaCallstackFormat(self):
+    language_type = None
+    format_type = CallStackFormatType.JAVA
+    self.assertIsNone(
+        StackFrame.Parse(language_type, format_type, 'dummy line', {}))
 
     deps = {'org/': Dependency('org/', 'https://repo', '1')}
-    stack.ParseLine('  at org.a.b(a.java:609)', deps)
+    frame = StackFrame.Parse(language_type, format_type,
+        '  at org.a.b(a.java:609)', deps)
     self._VerifyTwoStackFramesEqual(
-        stack[0],
+        frame,
         StackFrame(0, 'org/', 'org.a.b', 'a.java', 'org/a.java', [609]))
 
-  def testParseLineForSyzyasanCallstackFormat(self):
-    stack = CallStack(0, CallStackFormatType.SYZYASAN)
-
-    stack.ParseLine('dummy line', {})
-    self.assertEqual(stack, [])
+  def testParseStackFrameForSyzyasanCallstackFormat(self):
+    language_type = None
+    format_type = CallStackFormatType.SYZYASAN
+    self.assertIsNone(
+        StackFrame.Parse(language_type, format_type, 'dummy line', {}))
 
     deps = {'src/content/': Dependency('src/content/', 'https://repo', '1')}
-    stack.ParseLine('c::p::n [src/content/e.cc @ 165]', deps)
+    frame = StackFrame.Parse(language_type, format_type,
+        'c::p::n [src/content/e.cc @ 165]', deps)
     self._VerifyTwoStackFramesEqual(
-        stack[0],
+        frame,
         StackFrame(
             0, 'src/content/', 'c::p::n', 'e.cc', 'src/content/e.cc', [165]))
 
-  def testParseLineForDefaultCallstackFormat(self):
-    stack = CallStack(0, CallStackFormatType.DEFAULT)
-
-    stack.ParseLine('dummy line', {})
-    self.assertEqual(stack, [])
-
-    stack.ParseLine('#dummy line', {})
-    self.assertEqual(stack, [])
+  def testParseStackFrameForDefaultCallstackFormat(self):
+    language_type = None
+    format_type = CallStackFormatType.DEFAULT
+    self.assertIsNone(
+        StackFrame.Parse(language_type, format_type, 'dummy line', {}))
 
     deps = {'tp/webrtc/': Dependency('tp/webrtc/', 'https://repo', '1')}
-    stack.ParseLine('#0 0x52617a in func0 tp/webrtc/a.c:38:3', deps)
+    frame = StackFrame.Parse(language_type, format_type,
+        '#0 0x52617a in func0 tp/webrtc/a.c:38:3', deps)
     self._VerifyTwoStackFramesEqual(
-        stack[0],
+        frame,
         StackFrame(
             0, 'tp/webrtc/', 'func0', 'a.c', 'tp/webrtc/a.c', [38, 39, 40, 41]))
 
-    stack.ParseLine('#1 0x526 in func::func2::func3 tp/webrtc/a.c:3:2', deps)
+    frame = StackFrame.Parse(language_type, format_type,
+        '#1 0x526 in func::func2::func3 tp/webrtc/a.c:3:2', deps)
     self._VerifyTwoStackFramesEqual(
-        stack[1],
+        frame,
         StackFrame(
             1, 'tp/webrtc/', 'func::func2::func3', 'a.c', 'tp/webrtc/a.c',
             [3, 4, 5]))
 
-  def testParseLineForFracasJavaStack(self):
-    stack = CallStack(0, CallStackFormatType.DEFAULT,
-                      CallStackLanguageType.JAVA)
+  def testParseStackFrameForFracasJavaStack(self):
+    format_type = CallStackFormatType.DEFAULT
+    language_type = CallStackLanguageType.JAVA
 
-    stack.ParseLine('#0 0xxx in android.app.func app.java:2450', {})
+    frame = StackFrame.Parse(language_type, format_type,
+        '#0 0xxx in android.app.func app.java:2450', {})
     self._VerifyTwoStackFramesEqual(
-        stack[0],
+        frame,
         StackFrame(
             0, '', 'android.app.func', 'android/app.java',
             'android/app.java', [2450]))
@@ -160,13 +184,12 @@ class StacktraceTest(StacktraceTestSuite):
     self.assertEqual(stacktrace.crash_stack, None)
 
     callstack_list = [CallStack(0), CallStack(1)]
-    stacktrace.extend(callstack_list)
+    stacktrace = Stacktrace(stack_list=callstack_list)
 
     self._VerifyTwoCallStacksEqual(stacktrace.crash_stack,
                                    callstack_list[0])
 
   def testInitStacktaceByCopyAnother(self):
-    stack_trace = Stacktrace()
-    stack_trace.extend([CallStack(0), CallStack(1)])
+    stack_trace = Stacktrace(stack_list=[CallStack(0), CallStack(1)])
 
     self._VerifyTwoStacktracesEqual(Stacktrace(stack_trace), stack_trace)