diff --git a/Gemfile.lock b/Gemfile.lock
index 3024026..73d836c 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -96,7 +96,7 @@ GEM
       simplecov-rcov (~> 0.3, >= 0.3.7)
       simplecov_json_formatter (~> 0.1, >= 0.1.4)
       version_gem (~> 1.1, >= 1.1.8)
-    kettle-test (1.0.10)
+    kettle-test (2.0.1)
       appraisal2 (~> 3.0, >= 3.0.2)
       backports (~> 3.0)
       rspec (~> 3.0)
@@ -106,6 +106,7 @@ GEM
       rspec_junit_formatter (~> 0.6)
       silent_stream (~> 1.0, >= 1.0.12)
       timecop-rspec (~> 1.0, >= 1.0.3)
+      turbo_tests2 (~> 3.0)
       version_gem (~> 1.1, >= 1.1.9)
     kramdown (2.5.1)
       rexml (>= 3.3.9)
@@ -120,6 +121,8 @@ GEM
       racc (~> 1.4)
     ostruct (0.6.3)
     parallel (1.27.0)
+    parallel_tests (5.7.0)
+      parallel
     parser (3.3.10.1)
       ast (~> 2.4.1)
       racc
@@ -167,7 +170,7 @@ GEM
     rspec-expectations (3.13.5)
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.13.0)
-    rspec-mocks (3.13.7)
+    rspec-mocks (3.13.8)
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.13.0)
     rspec-pending_for (0.1.20)
@@ -283,7 +286,7 @@ GEM
     terminal-table (4.0.0)
       unicode-display_width (>= 1.1.1, < 4)
     thor (1.5.0)
-    timecop (0.9.10)
+    timecop (0.9.11)
     timecop-rspec (1.0.3)
       delegate (~> 0.1)
       rspec (~> 3.0)
@@ -291,6 +294,10 @@ GEM
     tsort (0.2.0)
     ttfunk (1.8.0)
       bigdecimal (~> 3.1)
+    turbo_tests2 (3.0.0)
+      parallel_tests (>= 3.3.0, < 6)
+      rspec (>= 3.10)
+      version_gem (~> 1.1, >= 1.1.9)
     unicode-display_width (3.2.0)
       unicode-emoji (~> 4.1)
     unicode-emoji (4.2.0)
@@ -320,7 +327,7 @@ DEPENDENCIES
   irb (~> 1.15, >= 1.15.2)
   kettle-dev (~> 2.0)
   kettle-soup-cover (~> 1.0, >= 1.0.10)
-  kettle-test (~> 1.0, >= 1.0.6)
+  kettle-test (~> 2.0, >= 1.0.6)
   kramdown (~> 2.5, >= 2.5.1)
   kramdown-parser-gfm (~> 1.1)
   mutex_m (~> 0.2)
diff --git a/yaml-converter.gemspec b/yaml-converter.gemspec
index 6cdf144..9c31c90 100644
--- a/yaml-converter.gemspec
+++ b/yaml-converter.gemspec
@@ -117,7 +117,7 @@ Gem::Specification.new do |spec|
 
   # Testing
   spec.add_development_dependency("appraisal2", "~> 3.0")                           # ruby >= 1.8.7, for testing against multiple versions of dependencies
-  spec.add_development_dependency("kettle-test", "~> 1.0", ">= 1.0.6")              # ruby >= 2.3
+  spec.add_development_dependency("kettle-test", ">= 1.0.6", "~> 2.0")              # ruby >= 2.3
 
   # Releasing
   spec.add_development_dependency("ruby-progressbar", "~> 1.13")                    # ruby >= 0