Write more tests for debugger

hera/debugger.py

@@ -62,26 +62,35 @@ def loop(self):
             if not response:
                 continue
 
-            cmd, *args = response.split()
-            cmd = cmd.lower()
-            if "break".startswith(cmd):
-                self.exec_break(args)
-            elif "continue".startswith(cmd):
-                self.exec_continue(args)
-            elif "next".startswith(cmd):
-                self.exec_next(args)
-            elif "print".startswith(cmd):
-                self.exec_print(args)
-            elif "restart".startswith(cmd):
-                self.exec_restart(args)
-            elif "skip".startswith(cmd):
-                self.exec_skip(args)
-            elif "quit".startswith(cmd):
+            if not self.handle_command(response):
                 break
-            elif "help".startswith(cmd):
-                print(_HELP_MSG)
-            else:
-                print('Unknown command "{}"'.format(cmd))
+
+    def handle_command(self, response):
+        """Parse the command and execute it. Return False if the loop should exit, and
+        True otherwise.
+        """
+        cmd, *args = response.split()
+        cmd = cmd.lower()
+        if "break".startswith(cmd):
+            self.exec_break(args)
+        elif "continue".startswith(cmd):
+            self.exec_continue(args)
+        elif "next".startswith(cmd):
+            self.exec_next(args)
+        elif "print".startswith(cmd):
+            self.exec_print(args)
+        elif "restart".startswith(cmd):
+            self.exec_restart(args)
+        elif "skip".startswith(cmd):
+            self.exec_skip(args)
+        elif "help".startswith(cmd):
+            print(_HELP_MSG)
+        elif "quit".startswith(cmd):
+            return False
+        else:
+            print("{} is not a known command.".format(cmd))
+
+        return True
 
     def exec_break(self, args):
         if len(args) > 1:

test/test_debugger.py

@@ -1,4 +1,5 @@
 import pytest
+from unittest.mock import patch
 
 from hera.debugger import Debugger
 from hera.parser import parse
@@ -23,6 +24,152 @@ def debugger():
 SAMPLE_PROGRAM = preprocess(_tree, _symtab)
 
 
+def test_print_breakpoints(debugger, capsys):
+    should_continue = debugger.handle_command("break")
+
+    assert should_continue
+    assert capsys.readouterr().out == "No breakpoints set.\n"
+
+
+def test_set_breakpoint(debugger):
+    assert len(debugger.breakpoints) == 0
+
+    should_continue = debugger.handle_command("break 2")
+
+    assert should_continue
+    assert len(debugger.breakpoints) == 1
+    assert 0 in debugger.breakpoints
+    assert debugger.breakpoints[0] == "2"
+
+
+def test_set_breakpoint_not_on_line_of_code(debugger, capsys):
+    should_continue = debugger.handle_command("break 1")
+
+    assert should_continue
+    assert len(debugger.breakpoints) == 0
+    assert capsys.readouterr().out == "Error: could not find corresponding line.\n"
+
+
+def test_set_unparseable_breakpoint(debugger, capsys):
+    should_continue = debugger.handle_command("break $$$")
+
+    assert should_continue
+    assert len(debugger.breakpoints) == 0
+    assert capsys.readouterr().out == "Error: could not parse argument.\n"
+
+
+def test_execute_break_with_too_many_args(debugger, capsys):
+    should_continue = debugger.handle_command("break 1 2 3")
+
+    assert should_continue
+    assert len(debugger.breakpoints) == 0
+    assert capsys.readouterr().out == "break takes zero or one arguments.\n"
+
+
+def test_execute_abbreviated_break(debugger):
+    with patch("hera.debugger.Debugger.exec_break") as mock_exec_break:
+        debugger.handle_command("break 7")
+        assert mock_exec_break.call_count == 1
+
+        args = mock_exec_break.call_args[0]
+        assert len(args) == 1
+        assert args[0] == ["7"]
+
+        kwargs = mock_exec_break.call_args[1]
+        assert len(kwargs) == 0
+
+
+def test_execute_next(debugger):
+    assert debugger.vm.registers[1] == 0
+    assert debugger.vm.pc == 0
+
+    should_continue = debugger.handle_command("next")
+
+    assert should_continue
+    assert debugger.vm.registers[1] == 10
+    assert debugger.vm.pc == 2
+
+
+def test_execute_abbreviated_next(debugger):
+    with patch("hera.debugger.Debugger.exec_next") as mock_exec_next:
+        debugger.handle_command("n")
+        assert mock_exec_next.call_count == 1
+
+
+def test_execute_continue_with_breakpoint(debugger):
+    debugger.breakpoints[4] = ""
+
+    should_continue = debugger.handle_command("continue")
+
+    assert should_continue
+    assert debugger.vm.registers[1] == 10
+    assert debugger.vm.registers[2] == 32
+    assert debugger.vm.registers[3] == 0
+    assert debugger.vm.pc == 4
+
+
+def test_execute_continue_without_breakpoint(debugger):
+    should_continue = debugger.handle_command("continue")
+
+    assert should_continue
+    assert debugger.vm.registers[1] == 10
+    assert debugger.vm.registers[2] == 32
+    assert debugger.vm.registers[3] == 42
+    assert debugger.vm.pc == 5
+
+
+def test_execute_abbreviated_continue(debugger):
+    with patch("hera.debugger.Debugger.exec_continue") as mock_exec_continue:
+        debugger.handle_command("c")
+        assert mock_exec_continue.call_count == 1
+
+
+def test_print_register(debugger, capsys):
+    debugger.vm.registers[7] = 42
+
+    should_continue = debugger.handle_command("print r7")
+
+    assert should_continue
+    assert capsys.readouterr().out == "r7 = 0x002a = 42 = '*'\n"
+
+
+def test_print_invalid_register(debugger, capsys):
+    should_continue = debugger.handle_command("print r17")
+
+    assert should_continue
+    assert capsys.readouterr().out == "r17 is not a valid register.\n"
+
+
+def test_print_program_counter(debugger, capsys):
+    debugger.vm.pc = 7
+
+    should_continue = debugger.handle_command("print PC")
+
+    assert should_continue
+    assert capsys.readouterr().out == "PC = 7\n"
+
+
+def test_print_memory_location(debugger, capsys):
+    debugger.vm.assign_memory(97, 1000)
+
+    should_continue = debugger.handle_command("print m[97]")
+
+    assert should_continue
+    assert capsys.readouterr().out == "M[97] = 1000\n"
+
+
+def test_execute_quit(debugger):
+    assert debugger.handle_command("quit") is False
+    assert debugger.handle_command("q") is False
+
+
+def test_execute_unknown_command(debugger, capsys):
+    should_continue = debugger.handle_command("whatever")
+
+    assert should_continue
+    assert capsys.readouterr().out == "whatever is not a known command.\n"
+
+
 def test_resolve_location(debugger):
     assert debugger.resolve_location(2) == 0