Add truth value testing to those lldb Python objects with the IsValid() method definitions.
object.__nonzero__(self) is called to implement truth value testing and the built-in operation bool(),
via a simple delegation to self.IsValid().

Change tests under python_api/lldbutil to utilize this mechanism.

llvm-svn: 131494
diff --git a/lldb/test/python_api/lldbutil/frame/TestFrameUtils.py b/lldb/test/python_api/lldbutil/frame/TestFrameUtils.py
index cd4ba09..d581104 100644
--- a/lldb/test/python_api/lldbutil/frame/TestFrameUtils.py
+++ b/lldb/test/python_api/lldbutil/frame/TestFrameUtils.py
@@ -27,15 +27,15 @@
         exe = os.path.join(os.getcwd(), "a.out")
 
         target = self.dbg.CreateTarget(exe)
-        self.assertTrue(target.IsValid(), VALID_TARGET)
+        self.assertTrue(target, VALID_TARGET)
 
         breakpoint = target.BreakpointCreateByLocation("main.c", self.line)
-        self.assertTrue(breakpoint.IsValid(), VALID_BREAKPOINT)
+        self.assertTrue(breakpoint, VALID_BREAKPOINT)
 
         # Now launch the process, and do not stop at entry point.
         self.process = target.LaunchSimple(None, None, os.getcwd())
 
-        if not self.process.IsValid():
+        if not self.process:
             self.fail("SBTarget.LaunchProcess() failed")
         self.assertTrue(self.process.GetState() == lldb.eStateStopped,
                         PROCESS_STOPPED)
@@ -45,7 +45,7 @@
         frame0 = thread.GetFrameAtIndex(0)
         frame1 = thread.GetFrameAtIndex(1)
         parent = lldbutil.get_parent_frame(frame0)
-        self.assertTrue(parent.IsValid() and parent.GetFrameID() == frame1.GetFrameID())
+        self.assertTrue(parent and parent.GetFrameID() == frame1.GetFrameID())
         frame0_args = lldbutil.get_args_as_string(frame0)
         parent_args = lldbutil.get_args_as_string(parent)
         self.assertTrue(frame0_args and parent_args)
diff --git a/lldb/test/python_api/lldbutil/iter/TestLLDBIterator.py b/lldb/test/python_api/lldbutil/iter/TestLLDBIterator.py
index e71dcf95..cc94157 100644
--- a/lldb/test/python_api/lldbutil/iter/TestLLDBIterator.py
+++ b/lldb/test/python_api/lldbutil/iter/TestLLDBIterator.py
@@ -38,16 +38,16 @@
         exe = os.path.join(os.getcwd(), "a.out")
 
         target = self.dbg.CreateTarget(exe)
-        self.assertTrue(target.IsValid(), VALID_TARGET)
+        self.assertTrue(target, VALID_TARGET)
 
         breakpoint = target.BreakpointCreateByLocation("main.cpp", self.line1)
-        self.assertTrue(breakpoint.IsValid(), VALID_BREAKPOINT)
+        self.assertTrue(breakpoint, VALID_BREAKPOINT)
 
         # Now launch the process, and do not stop at entry point.
         rc = lldb.SBError()
         self.process = target.Launch (self.dbg.GetListener(), None, None, os.ctermid(), os.ctermid(), os.ctermid(), None, 0, False, rc)
 
-        if not rc.Success() or not self.process.IsValid():
+        if not rc.Success() or not self.process:
             self.fail("SBTarget.LaunchProcess() failed")
 
         from lldbutil import get_description
@@ -70,12 +70,12 @@
         exe = os.path.join(os.getcwd(), "a.out")
 
         target = self.dbg.CreateTarget(exe)
-        self.assertTrue(target.IsValid(), VALID_TARGET)
+        self.assertTrue(target, VALID_TARGET)
 
         breakpoint = target.BreakpointCreateByLocation("main.cpp", self.line1)
-        self.assertTrue(breakpoint.IsValid(), VALID_BREAKPOINT)
+        self.assertTrue(breakpoint, VALID_BREAKPOINT)
         breakpoint = target.BreakpointCreateByLocation("main.cpp", self.line2)
-        self.assertTrue(breakpoint.IsValid(), VALID_BREAKPOINT)
+        self.assertTrue(breakpoint, VALID_BREAKPOINT)
 
         self.assertTrue(target.GetNumBreakpoints() == 2)
 
@@ -99,16 +99,16 @@
         exe = os.path.join(os.getcwd(), "a.out")
 
         target = self.dbg.CreateTarget(exe)
-        self.assertTrue(target.IsValid(), VALID_TARGET)
+        self.assertTrue(target, VALID_TARGET)
 
         breakpoint = target.BreakpointCreateByLocation("main.cpp", self.line1)
-        self.assertTrue(breakpoint.IsValid(), VALID_BREAKPOINT)
+        self.assertTrue(breakpoint, VALID_BREAKPOINT)
 
         # Now launch the process, and do not stop at entry point.
         rc = lldb.SBError()
         self.process = target.Launch (self.dbg.GetListener(), None, None, os.ctermid(), os.ctermid(), os.ctermid(), None, 0, False, rc)
 
-        if not rc.Success() or not self.process.IsValid():
+        if not rc.Success() or not self.process:
             self.fail("SBTarget.LaunchProcess() failed")
 
         from lldbutil import print_stacktrace
diff --git a/lldb/test/python_api/lldbutil/iter/TestRegistersIterator.py b/lldb/test/python_api/lldbutil/iter/TestRegistersIterator.py
index 2fffd27..8e66d37 100644
--- a/lldb/test/python_api/lldbutil/iter/TestRegistersIterator.py
+++ b/lldb/test/python_api/lldbutil/iter/TestRegistersIterator.py
@@ -27,16 +27,16 @@
         exe = os.path.join(os.getcwd(), "a.out")
 
         target = self.dbg.CreateTarget(exe)
-        self.assertTrue(target.IsValid(), VALID_TARGET)
+        self.assertTrue(target, VALID_TARGET)
 
         breakpoint = target.BreakpointCreateByLocation("main.cpp", self.line1)
-        self.assertTrue(breakpoint.IsValid(), VALID_BREAKPOINT)
+        self.assertTrue(breakpoint, VALID_BREAKPOINT)
 
         # Now launch the process, and do not stop at entry point.
         rc = lldb.SBError()
         self.process = target.Launch (self.dbg.GetListener(), None, None, os.ctermid(), os.ctermid(), os.ctermid(), None, 0, False, rc)
 
-        if not rc.Success() or not self.process.IsValid():
+        if not rc.Success() or not self.process:
             self.fail("SBTarget.LaunchProcess() failed")
 
         import lldbutil
@@ -52,7 +52,7 @@
                     if self.TraceOn():
                         print "\nNumber of general purpose registers: %d" % num
                     for reg in REGs:
-                        self.assertTrue(reg.IsValid())
+                        self.assertTrue(reg)
                         if self.TraceOn():
                             print "%s => %s" % (reg.GetName(), reg.GetValue(frame))
 
@@ -61,7 +61,7 @@
                     if self.TraceOn():
                         print "\nNumber of floating point registers: %d" % num
                     for reg in REGs:
-                        self.assertTrue(reg.IsValid())
+                        self.assertTrue(reg)
                         if self.TraceOn():
                             print "%s => %s" % (reg.GetName(), reg.GetValue(frame))
 
@@ -70,7 +70,7 @@
                     if self.TraceOn():
                         print "\nNumber of exception state registers: %d" % num
                     for reg in REGs:
-                        self.assertTrue(reg.IsValid())
+                        self.assertTrue(reg)
                         if self.TraceOn():
                             print "%s => %s" % (reg.GetName(), reg.GetValue(frame))
 
@@ -79,7 +79,7 @@
                                  "Floating Point Registers",
                                  "Exception State Registers"]:
                         REGs = lldbutil.get_registers(frame, kind)
-                        self.assertTrue(REGs.IsValid())
+                        self.assertTrue(REGs)
 
                     # We've finished dumping the registers for frame #0.
                     break
diff --git a/lldb/test/python_api/lldbutil/process/TestPrintStackTraces.py b/lldb/test/python_api/lldbutil/process/TestPrintStackTraces.py
index 32ff8ac..43bf1eb 100644
--- a/lldb/test/python_api/lldbutil/process/TestPrintStackTraces.py
+++ b/lldb/test/python_api/lldbutil/process/TestPrintStackTraces.py
@@ -28,16 +28,16 @@
         exe = os.path.join(os.getcwd(), "a.out")
 
         target = self.dbg.CreateTarget(exe)
-        self.assertTrue(target.IsValid(), VALID_TARGET)
+        self.assertTrue(target, VALID_TARGET)
 
         breakpoint = target.BreakpointCreateByLocation("main.cpp", self.line)
-        self.assertTrue(breakpoint.IsValid(), VALID_BREAKPOINT)
+        self.assertTrue(breakpoint, VALID_BREAKPOINT)
 
         # Now launch the process, and do not stop at entry point.
         rc = lldb.SBError()
         self.process = target.Launch (self.dbg.GetListener(), None, None, os.ctermid(), os.ctermid(), os.ctermid(), None, 0, False, rc)
 
-        if not rc.Success() or not self.process.IsValid():
+        if not rc.Success() or not self.process:
             self.fail("SBTarget.LaunchProcess() failed")
 
         import lldbutil