(GH-199) Update stack trace tests for Puppet 6.11.0

The Puppet call stack has changed behaviour for both exceptions and succesful
calls.  This commit updates the tests for expect different stack traces for
exceptions, and updates the generate stack trace method to ignore call sites
with invalid line numbers (e.g. 0)

lib/puppet-debugserver/debug_session/hook_handlers.rb

@@ -256,7 +256,11 @@ def process_breakpoint_hook(reason, args)
         end
 
         break_description = break_display_text if break_description.empty?
-        stack_trace = Puppet::Pops::PuppetStack.stacktrace
+        # Due to a modification to the way stack traces are treated in Puppet 6.11.0, the stack
+        # now includes entries for files in Line 0, which doesn't exist. These indicate that a file
+        # has started to be processed/parsed/compiled. So we just ignore them
+        # See https://tickets.puppetlabs.com/browse/PUP-10150 for more infomation
+        stack_trace = Puppet::Pops::PuppetStack.stacktrace.reject { |item| item[1].zero? }
         # Due to https://github.com/puppetlabs/puppet/commit/0f96dd918b6184261bc2219e5e68e246ffbeac10
         # Prior to Puppet 4.8.0, stacktrace is in reverse order
         stack_trace.reverse! if Gem::Version.new(Puppet.version) < Gem::Version.new('4.8.0')

spec/debugserver/integration/puppet-debugserver/end_to_end_spec.rb

@@ -32,6 +32,12 @@
     @debug_stderr.close
   }
 
+  def modified_puppet_stack_trace
+    # Due to a modification to the way stack traces are treated in Puppet 6.11.0, the stack size is different
+    # See https://tickets.puppetlabs.com/browse/PUP-10150 for more infomation
+    @modified_puppet_stack_trace ||= Gem::Version.create(Puppet.version) >= Gem::Version.create('6.11.0')
+  end
+
   context 'Processing an empty manifest with no breakpoints' do
     let(:manifest_file) { File.join($fixtures_dir, 'environments', 'testfixtures', 'manifests', 'empty.pp') }
     let(:noop) { true }
@@ -92,10 +98,14 @@
       result = @client.data_from_request_seq_id(@client.current_seq_id)
       # As we're only in the root, only two frames should be available.  The error and where it was called from
       expect(result['success']).to be true
-      expect(result['body']['stackFrames'].count).to eq(2)
-      expect(result['body']['stackFrames'][0]).to include('line' => 3)
-      expect(result['body']['stackFrames'][1]).to include('line' => 3)
-
+      if modified_puppet_stack_trace
+        expect(result['body']['stackFrames'].count).to eq(1)
+        expect(result['body']['stackFrames'][0]).to include('line' => 3)
+      else
+        expect(result['body']['stackFrames'].count).to eq(2)
+        expect(result['body']['stackFrames'][0]).to include('line' => 3)
+        expect(result['body']['stackFrames'][1]).to include('line' => 3)
+      end
       # continue_request
       @client.send_data(@client.continue_request(@client.next_seq_id, thread_id))
       expect(@client).to receive_message_with_request_id_within_timeout([@client.current_seq_id, 5])