diff --git a/spec/integration/committing_spec.rb b/spec/integration/committing_spec.rb
index 1e1f65a6..9f9071fe 100644
--- a/spec/integration/committing_spec.rb
+++ b/spec/integration/committing_spec.rb
@@ -19,7 +19,7 @@
   around do |example|
     repo do
       File.open('.overcommit.yml', 'w') { |f| f.write(config) }
-      `overcommit --install > #{File::NULL}`
+      install_overcommit_hooks
       example.run
     end
   end
@@ -71,7 +71,7 @@
 
   around do |example|
     repo do
-      `overcommit --install > #{File::NULL}`
+      install_overcommit_hooks
       File.open('.overcommit.yml', 'w') { |f| f.write(config) }
       File.open('test.txt', 'w') { |f| f.write(file_contents) }
       `git add test.txt`
diff --git a/spec/integration/configuration_signing_spec.rb b/spec/integration/configuration_signing_spec.rb
index 0b1e0b38..3757962e 100644
--- a/spec/integration/configuration_signing_spec.rb
+++ b/spec/integration/configuration_signing_spec.rb
@@ -29,7 +29,7 @@
 
   around do |example|
     repo do
-      `overcommit --install > #{File::NULL}`
+      install_overcommit_hooks
       echo(config.to_yaml, '.overcommit.yml')
 
       `overcommit --sign` if configuration_signed
diff --git a/spec/integration/disable_overcommit_spec.rb b/spec/integration/disable_overcommit_spec.rb
index 04243cd5..3acbe06c 100644
--- a/spec/integration/disable_overcommit_spec.rb
+++ b/spec/integration/disable_overcommit_spec.rb
@@ -7,7 +7,7 @@
 
   around do |example|
     repo do
-      `overcommit --install > #{File::NULL}`
+      install_overcommit_hooks
       Overcommit::Utils.with_environment('OVERCOMMIT_DISABLE' => overcommit_disable) do
         touch 'blah'
         `git add blah`
diff --git a/spec/integration/hook_signing_spec.rb b/spec/integration/hook_signing_spec.rb
index 6392a64e..a69ba321 100644
--- a/spec/integration/hook_signing_spec.rb
+++ b/spec/integration/hook_signing_spec.rb
@@ -48,7 +48,7 @@
     around do |example|
       repo do
         echo(config.to_yaml, '.overcommit.yml')
-        `overcommit --install > #{File::NULL}`
+        install_overcommit_hooks
 
         echo(hook_script, script_path)
         FileUtils.chmod(0o755, script_path)
@@ -87,7 +87,7 @@
     around do |example|
       repo do
         echo(config.to_yaml, '.overcommit.yml')
-        `overcommit --install > #{File::NULL}`
+        install_overcommit_hooks
 
         echo(hook_script, script_path)
         FileUtils.chmod(0o755, script_path)
diff --git a/spec/integration/parallelize_spec.rb b/spec/integration/parallelize_spec.rb
index ede55b38..5641a003 100644
--- a/spec/integration/parallelize_spec.rb
+++ b/spec/integration/parallelize_spec.rb
@@ -23,7 +23,7 @@
   around do |example|
     repo do
       File.open('.overcommit.yml', 'w') { |f| f.write(config) }
-      `overcommit --install > #{File::NULL}`
+      install_overcommit_hooks
       example.run
     end
   end
diff --git a/spec/integration/protected_branches_spec.rb b/spec/integration/protected_branches_spec.rb
index 115be29d..7b5d32e5 100644
--- a/spec/integration/protected_branches_spec.rb
+++ b/spec/integration/protected_branches_spec.rb
@@ -61,7 +61,7 @@
   end
 
   shared_context 'ProtectedBranches enabled' do
-    before { `overcommit --install > #{File::NULL}` }
+    before { install_overcommit_hooks }
   end
 
   shared_examples 'push succeeds' do
diff --git a/spec/integration/resolving_cherry_pick_conflict_spec.rb b/spec/integration/resolving_cherry_pick_conflict_spec.rb
index fbe542f4..4ecae27f 100644
--- a/spec/integration/resolving_cherry_pick_conflict_spec.rb
+++ b/spec/integration/resolving_cherry_pick_conflict_spec.rb
@@ -30,7 +30,7 @@
       `git commit -m "Add Branch 2 addition"`
       `git checkout -q master`
       `git cherry-pick branch1 > #{File::NULL} 2>&1`
-      `overcommit --install > #{File::NULL}`
+      install_overcommit_hooks
       `git cherry-pick branch2 > #{File::NULL} 2>&1` # Results in cherry-pick conflict
       echo('Conflicts Resolved ', 'some-file') # Fail trailing whitespace hook
       `git add some-file`
diff --git a/spec/integration/resolving_merge_conflict_spec.rb b/spec/integration/resolving_merge_conflict_spec.rb
index 997dcb09..201617dc 100644
--- a/spec/integration/resolving_merge_conflict_spec.rb
+++ b/spec/integration/resolving_merge_conflict_spec.rb
@@ -22,7 +22,7 @@
       `git checkout -q master`
       `git merge branch1`
       `git merge branch2` # Results in merge conflict
-      `overcommit --install > #{File::NULL}`
+      install_overcommit_hooks
       echo('Conflicts Resolved', 'some-file')
       `git add some-file`
       example.run
diff --git a/spec/integration/worktree_signing_spec.rb b/spec/integration/worktree_signing_spec.rb
index 1468a197..c992829b 100644
--- a/spec/integration/worktree_signing_spec.rb
+++ b/spec/integration/worktree_signing_spec.rb
@@ -33,7 +33,7 @@
       raise "Unable to create worktree: #{result.stderr}" unless result.success?
 
       echo(config.to_yaml, '.overcommit.yml')
-      `overcommit --install > #{File::NULL}`
+      install_overcommit_hooks
       `overcommit --sign`
 
       Dir.chdir(linked_worktree) do
diff --git a/spec/support/fixture_installation.rb b/spec/support/fixture_installation.rb
new file mode 100644
index 00000000..2fcb8d67
--- /dev/null
+++ b/spec/support/fixture_installation.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+require 'stringio'
+
+# Prepare installed hooks without booting a separate fixture CLI process.
+# CLI and Gemfile-loading integration tests still invoke the real executable.
+module ShellHelpers
+  def install_overcommit_hooks
+    %w[repo_root git_dir].each { |name| Overcommit::Utils.instance_variable_set("@#{name}", nil) }
+    logger = Overcommit::Logger.new(StringIO.new)
+    Overcommit::Installer.new(logger).run(Dir.pwd, action: :install)
+  ensure
+    %w[repo_root git_dir].each { |name| Overcommit::Utils.instance_variable_set("@#{name}", nil) }
+  end
+end