diff --git a/rubygem-bundler_ext-0.4.1-Fix-Bundler-1.8.1-test-failures.patch b/rubygem-bundler_ext-0.4.1-Fix-Bundler-1.8.1-test-failures.patch
new file mode 100644
index 0000000..a8818ff
--- /dev/null
+++ b/rubygem-bundler_ext-0.4.1-Fix-Bundler-1.8.1-test-failures.patch
@@ -0,0 +1,72 @@
+From e4e583af5539e9d9ec0d859721025cae4c290181 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?V=C3=ADt=20Ondruch?= <vondruch@redhat.com>
+Date: Wed, 16 Sep 2020 14:40:35 +0200
+Subject: [PATCH] Fix Bundler 1.8.1+ test failures.
+
+This fixes issues such as:
+
+  1) BundlerExt::Runtime add_spec adds spec load paths not already on LOAD_PATH to it
+     Failure/Error: runtime.add_spec(spec)
+     LoadError:
+       cannot load such file -- rubygems/ext/builder
+     # /usr/share/rubygems/rubygems/core_ext/kernel_require.rb:83:in `require'
+     # /usr/share/rubygems/rubygems/core_ext/kernel_require.rb:83:in `require'
+     # ./lib/bundler_ext/runtime.rb:20:in `new'
+     # ./lib/bundler_ext/runtime.rb:20:in `rubygems'
+     # ./lib/bundler_ext/runtime.rb:64:in `add_spec'
+     # ./spec/bundler_ext/runtime_spec.rb:164:in `block (3 levels) in <module:BundlerExt>'
+     # ./spec/bundler_ext/runtime_spec.rb:145:in `block (3 levels) in <module:BundlerExt>'
+
+These are caused by Bundler requiring to load additional libraries [[1]]
+since Bundler 1.8.1.
+
+[1]: https://github.com/rubygems/bundler/commit/f86bd0712c3a1ed8138e5c0a056d6a5511e207c9
+---
+ spec/bundler_ext/runtime_spec.rb | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/spec/bundler_ext/runtime_spec.rb b/spec/bundler_ext/runtime_spec.rb
+index 2f246d0..edcc40f 100644
+--- a/spec/bundler_ext/runtime_spec.rb
++++ b/spec/bundler_ext/runtime_spec.rb
+@@ -141,7 +141,7 @@ module BundlerExt
+ 
+     describe "add_spec" do
+       around(:each) do |spec|
+-        orig = $LOAD_PATH
++        orig = $LOAD_PATH.dup
+         spec.run
+ 
+         # XXX need to restore this way else we'll get an err:
+@@ -150,9 +150,11 @@ module BundlerExt
+         orig.each { |o| $LOAD_PATH << o }
+       end
+ 
++      # XXX needed to require rubygems/ext/builder in with Bundler 1.8.1+.
++      let!(:runtime) { described_class.new.tap {|c| c.rubygems} }
++
+       it "marks spec as loaded" do
+         spec = Gem::Specification.new
+-        runtime = described_class.new
+         runtime.rubygems.should_receive(:mark_loaded).with(spec)
+         runtime.add_spec(spec)
+       end
+@@ -160,7 +162,6 @@ module BundlerExt
+       it "adds spec load paths not already on LOAD_PATH to it" do
+         $LOAD_PATH.clear
+         spec = Gem::Specification.new :load_paths => ['foo']
+-        runtime = described_class.new
+         runtime.add_spec(spec)
+         $LOAD_PATH.should include(*spec.load_paths)
+       end
+@@ -169,7 +170,6 @@ module BundlerExt
+         spec = Gem::Specification.new :load_paths => ['foo']
+         $LOAD_PATH.clear
+         $LOAD_PATH << spec.load_paths.first
+-        runtime = described_class.new
+         runtime.add_spec(spec)
+         $LOAD_PATH.size.should == 1
+       end
+-- 
+2.27.0
+
diff --git a/rubygem-bundler_ext.spec b/rubygem-bundler_ext.spec
index 0d0e455..ee0b77d 100644
--- a/rubygem-bundler_ext.spec
+++ b/rubygem-bundler_ext.spec
@@ -4,13 +4,16 @@
 Summary: Load system gems via Bundler DSL
 Name: rubygem-%{gem_name}
 Version: 0.4.1
-Release: 10%{?dist}
+Release: 11%{?dist}
 License: MIT
 URL: https://github.com/bundlerext/bundler_ext
 Source0: http://rubygems.org/gems/%{gem_name}-%{version}.gem
+# Fix test failures due to Bundler 1.8.1+.
+# https://github.com/bundlerext/bundler_ext/pull/22
+Patch0: rubygem-bundler_ext-0.4.1-Fix-Bundler-1.8.1-test-failures.patch
 BuildRequires: ruby(release)
 BuildRequires: rubygems-devel
-BuildRequires: ruby 
+BuildRequires: ruby
 BuildRequires: rubygem(rspec) < 3
 BuildRequires: rubygem(bundler)
 BuildRequires: rubygem(rails)
@@ -30,22 +33,30 @@ BuildArch: noarch
 Documentation for %{name}.
 
 %prep
-%setup -q -c -T
-%gem_install -n %{SOURCE0}
+%setup -q -n %{gem_name}-%{version}
+
+%patch0 -p1
 
 %build
+# Create the gem as gem install only works on a gem file
+gem build ../%{gem_name}-%{version}.gemspec
+
+# %%gem_install compiles any C extensions and installs the gem into ./%%gem_dir
+# by default, so that we can move it into the buildroot in %%install
+%gem_install
 
 %install
 mkdir -p %{buildroot}%{gem_dir}
-cp -pa .%{gem_dir}/* \
+cp -a .%{gem_dir}/* \
         %{buildroot}%{gem_dir}/
 
+
+
 %check
 pushd .%{gem_instdir}
 rspec2 spec
 popd
 
-
 %files
 %dir %{gem_instdir}
 %exclude %{gem_instdir}/.*
@@ -59,9 +70,13 @@ popd
 %doc %{gem_instdir}/CHANGELOG
 %doc %{gem_instdir}/README.md
 %{gem_instdir}/Rakefile
-%{gem_instdir}/spec/
+%{gem_instdir}/spec
 
 %changelog
+* Wed Sep 16 2020 Vít Ondruch <vondruch@redhat.com> - 0.4.1-1
+- Fix FTBFS due to test failures with Bundler 1.8.1+.
+  Resolves: rhbz#1865408
+
 * Sat Aug 01 2020 Fedora Release Engineering <releng@fedoraproject.org> - 0.4.1-10
 - Second attempt - Rebuilt for
   https://fedoraproject.org/wiki/Fedora_33_Mass_Rebuild