Narrow the tracing of object allocations to during each test

tool/lib/minitest/unit.rb

@@ -961,8 +961,11 @@ module MiniTest
       }
 
       leakchecker = LeakChecker.new
+      if ENV["LEAK_CHECKER_TRACE_OBJECT_ALLOCATION"]
+        require "objspace"
+        trace = true
+      end
 
-      continuation = proc do
       assertions = filtered_test_methods.map { |method|
         inst = suite.new method
         inst._assertions = 0
@@ -970,7 +973,12 @@ module MiniTest
         print "#{suite}##{method} = " if @verbose
 
         start_time = Time.now if @verbose
-          result = inst.run self
+        result =
+          if trace
+            ObjectSpace.trace_object_allocations {inst.run self}
+          else
+            inst.run self
+          end
 
         print "%.2f s = " % (Time.now - start_time) if @verbose
         print result
@@ -986,14 +994,6 @@ module MiniTest
       return assertions.size, assertions.inject(0) { |sum, n| sum + n }
     end
 
-      if ENV["LEAK_CHECKER_TRACE_OBJECT_ALLOCATION"]
-        require "objspace"
-        ObjectSpace.trace_object_allocations(&continuation)
-      else
-        continuation.call
-      end
-    end
-
     ##
     # Record the result of a single test. Makes it very easy to gather
     # information. Eg: