6 files changed, 21 insertions, 11 deletions
diff --git a/test/-ext-/integer/test_integer.rb b/test/-ext-/integer/test_integer.rb
index 6ea42e3133..000cb78e4e 100644
--- a/test/-ext-/integer/test_integer.rb
+++ b/test/-ext-/integer/test_integer.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: false
 require 'test/unit'
+require '-test-/integer'
 
 class TestInteger < Test::Unit::TestCase
   FIXNUM_MIN = Integer::FIXNUM_MIN
diff --git a/test/-ext-/num2int/test_num2int.rb b/test/-ext-/num2int/test_num2int.rb
index da3bf97ecd..8eedc50db1 100644
--- a/test/-ext-/num2int/test_num2int.rb
+++ b/test/-ext-/num2int/test_num2int.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: false
 require 'test/unit'
 require '-test-/num2int'
+require '-test-/integer'
 
 class TestNum2int < Test::Unit::TestCase
   SHRT_MIN = -32768
diff --git a/test/lib/-test-/integer.rb b/test/lib/-test-/integer.rb
new file mode 100644
index 0000000000..a224148f24
--- /dev/null
+++ b/test/lib/-test-/integer.rb
@@ -0,0 +1,14 @@
+require 'test/unit'
+require '-test-/integer.so'
+
+module Test::Unit::Assertions
+  def assert_fixnum(v, msg=nil)
+    assert_instance_of(Integer, v, msg)
+    assert_predicate(v, :fixnum?, msg)
+  end
+
+  def assert_bignum(v, msg=nil)
+    assert_instance_of(Integer, v, msg)
+    assert_predicate(v, :bignum?, msg)
+  end
+end
diff --git a/test/lib/test/unit.rb b/test/lib/test/unit.rb
index df7070e3fc..d34e11afa7 100644
--- a/test/lib/test/unit.rb
+++ b/test/lib/test/unit.rb
@@ -8,7 +8,6 @@ require 'test/unit/assertions'
 require_relative '../envutil'
 require 'test/unit/testcase'
 require 'optparse'
-require '-test-/testutil'
 
 # See Test::Unit
 module Test
diff --git a/test/lib/test/unit/assertions.rb b/test/lib/test/unit/assertions.rb
index 2a75871d7d..91532e8ff8 100644
--- a/test/lib/test/unit/assertions.rb
+++ b/test/lib/test/unit/assertions.rb
@@ -771,16 +771,6 @@ eom
         values
       end
 
-      def assert_fixnum(v, msg=nil)
-        assert_instance_of(Integer, v, msg)
-        assert_predicate(v, :fixnum?, msg)
-      end
-
-      def assert_bignum(v, msg=nil)
-        assert_instance_of(Integer, v, msg)
-        assert_predicate(v, :bignum?, msg)
-      end
-
       class << (AssertFile = Struct.new(:failure_message).new)
         include Assertions
         def assert_file_predicate(predicate, *args)
diff --git a/test/ruby/test_bignum.rb b/test/ruby/test_bignum.rb
index 7760062edc..e19c3202ed 100644
--- a/test/ruby/test_bignum.rb
+++ b/test/ruby/test_bignum.rb
@@ -1,5 +1,9 @@
 # frozen_string_literal: false
 require 'test/unit'
+begin
+  require '-test-/integer'
+rescue LoadError
+else
 
 class TestBignum < Test::Unit::TestCase
   FIXNUM_MIN = Integer::FIXNUM_MIN
@@ -734,3 +738,4 @@ class TestBignum < Test::Unit::TestCase
     assert_equal(T1024 ^ 10, T1024 ^ obj)
   end
 end
+end