[Feature #16513] TracePoint#inspect returns "... file:line" (#3391)

* Fix debug documents to match Thread#to_s change (Feature #16412 ticket)

* TracePoint#inspect returns "... file:line" (Feature #16513)

* Guard older version of Ruby in Tracepoint inspection tests

* Focus on current thread only when running TracePoint inspection test

spec/ruby/core/tracepoint/inspect_spec.rb

@@ -2,6 +2,18 @@ require_relative '../../spec_helper'
 require_relative 'fixtures/classes'
 
 describe 'TracePoint#inspect' do
+  before do
+    ruby_version_is ""..."2.8" do
+      # Old behavior for Ruby < 2.8
+      @path_prefix = '@'
+    end
+
+    ruby_version_is "2.8" do
+      # New behavior for Ruby >= 2.8
+      @path_prefix = ' '
+    end
+  end
+
   it 'returns a string containing a human-readable TracePoint status' do
     TracePoint.new(:line) {}.inspect.should == '#<TracePoint:disabled>'
   end
@@ -16,7 +28,54 @@ describe 'TracePoint#inspect' do
       line = __LINE__
     end
 
-    inspect.should == "#<TracePoint:line@#{__FILE__}:#{line}>"
+    inspect.should == "#<TracePoint:line#{@path_prefix}#{__FILE__}:#{line}>"
+  end
+
+  it 'returns a String showing the event, method, path and line for a :call event' do
+    inspect = nil
+    line = nil
+    TracePoint.new(:call) { |tp|
+      next unless TracePointSpec.target_thread?
+      inspect ||= tp.inspect
+    }.enable do
+      line = __LINE__ + 1
+      def trace_point_spec_test_call; end
+      trace_point_spec_test_call
+    end
+
+    inspect.should == "#<TracePoint:call `trace_point_spec_test_call'#{@path_prefix}#{__FILE__}:#{line}>"
+  end
+
+  it 'returns a String showing the event, method, path and line for a :return event' do
+    inspect = nil
+    line = nil
+    TracePoint.new(:return) { |tp|
+      next unless TracePointSpec.target_thread?
+      inspect ||= tp.inspect
+    }.enable do
+      line = __LINE__ + 4
+      def trace_point_spec_test_return
+        a = 1
+        return a
+      end
+      trace_point_spec_test_return
+    end
+
+    inspect.should == "#<TracePoint:return `trace_point_spec_test_return'#{@path_prefix}#{__FILE__}:#{line}>"
+  end
+
+  it 'returns a String showing the event, method, path and line for a :c_call event' do
+    inspect = nil
+    line = nil
+    TracePoint.new(:c_call) { |tp|
+      next unless TracePointSpec.target_thread?
+      inspect ||= tp.inspect
+    }.enable do
+      line = __LINE__ + 1
+      [0, 1].max
+    end
+
+    inspect.should == "#<TracePoint:c_call `max'#{@path_prefix}#{__FILE__}:#{line}>"
   end
 
   it 'returns a String showing the event, path and line for a :class event' do
@@ -31,6 +90,38 @@ describe 'TracePoint#inspect' do
       end
     end
 
-    inspect.should == "#<TracePoint:class@#{__FILE__}:#{line}>"
+    inspect.should == "#<TracePoint:class#{@path_prefix}#{__FILE__}:#{line}>"
+  end
+
+  it 'returns a String showing the event and thread for :thread_begin event' do
+    inspect = nil
+    thread = nil
+    thread_inspection = nil
+    TracePoint.new(:thread_begin) { |tp|
+      next unless Thread.current == thread
+      inspect ||= tp.inspect
+    }.enable do
+      thread = Thread.new {}
+      thread_inspection = thread.inspect
+      thread.join
+    end
+
+    inspect.should == "#<TracePoint:thread_begin #{thread_inspection}>"
+  end
+
+  it 'returns a String showing the event and thread for :thread_end event' do
+    inspect = nil
+    thread = nil
+    thread_inspection = nil
+    TracePoint.new(:thread_end) { |tp|
+      next unless Thread.current == thread
+      inspect ||= tp.inspect
+    }.enable do
+      thread = Thread.new {}
+      thread_inspection = thread.inspect
+      thread.join
+    end
+
+    inspect.should == "#<TracePoint:thread_end #{thread_inspection}>"
   end
 end