diff --git a/Library/Homebrew/cask/artifact/bashcompletion.rb b/Library/Homebrew/cask/artifact/bashcompletion.rb
index e42f1085ca..3ffe7c6833 100644
--- a/Library/Homebrew/cask/artifact/bashcompletion.rb
+++ b/Library/Homebrew/cask/artifact/bashcompletion.rb
@@ -9,7 +9,7 @@ module Cask
     class BashCompletion < ShellCompletion
       sig { params(target: T.any(String, Pathname)).returns(Pathname) }
       def resolve_target(target)
-        name = if target.to_s.end_with? ".bash"
+        name = if File.extname(target).nil?
           target
         else
           new_name = File.basename(target, File.extname(target))
diff --git a/Library/Homebrew/test/cask/artifact/bashcompletion_spec.rb b/Library/Homebrew/test/cask/artifact/bashcompletion_spec.rb
new file mode 100644
index 0000000000..3bdfec62f4
--- /dev/null
+++ b/Library/Homebrew/test/cask/artifact/bashcompletion_spec.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+RSpec.describe Cask::Artifact::BashCompletion, :cask do
+  let(:cask) { Cask::CaskLoader.load(cask_token) }
+
+  context "with install" do
+    let(:install_phase) do
+      lambda do
+        cask.artifacts.select { |a| a.is_a?(described_class) }.each do |artifact|
+          artifact.install_phase(command: NeverSudoSystemCommand, force: false)
+        end
+      end
+    end
+
+    let(:source_path) { cask.staged_path.join("test.bash") }
+    let(:target_path) { cask.config.bash_completion.join("test") }
+    let(:full_source_path) { cask.staged_path.join("test.bash-completion") }
+    let(:full_target_path) { cask.config.bash_completion.join("test") }
+
+    before do
+      InstallHelper.install_without_artifacts(cask)
+    end
+
+    context "with completion" do
+      let(:cask_token) { "with-shellcompletion" }
+
+      it "links the completion to the proper directory" do
+        install_phase.call
+
+        expect(File).to be_identical target_path, source_path
+      end
+    end
+
+    context "with long completion" do
+      let(:cask_token) { "with-shellcompletion-long" }
+
+      it "links the completion to the proper directory" do
+        install_phase.call
+
+        expect(File).to be_identical full_target_path, full_source_path
+      end
+    end
+  end
+end
diff --git a/Library/Homebrew/test/cask/artifact/fishlcompletion_spec.rb b/Library/Homebrew/test/cask/artifact/fishlcompletion_spec.rb
new file mode 100644
index 0000000000..f5e166ff45
--- /dev/null
+++ b/Library/Homebrew/test/cask/artifact/fishlcompletion_spec.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+RSpec.describe Cask::Artifact::FishCompletion, :cask do
+  let(:cask) { Cask::CaskLoader.load(cask_token) }
+
+  context "with install" do
+    let(:install_phase) do
+      lambda do
+        cask.artifacts.select { |a| a.is_a?(described_class) }.each do |artifact|
+          artifact.install_phase(command: NeverSudoSystemCommand, force: false)
+        end
+      end
+    end
+
+    let(:source_path) { cask.staged_path.join("test.fish") }
+    let(:target_path) { cask.config.fish_completion.join("test.fish") }
+    let(:full_source_path) { cask.staged_path.join("test.fish-completion") }
+    let(:full_target_path) { cask.config.fish_completion.join("test.fish") }
+
+    before do
+      InstallHelper.install_without_artifacts(cask)
+    end
+
+    context "with completion" do
+      let(:cask_token) { "with-shellcompletion" }
+
+      it "links the completion to the proper directory" do
+        install_phase.call
+
+        expect(File).to be_identical target_path, source_path
+      end
+    end
+
+    context "with long completion" do
+      let(:cask_token) { "with-shellcompletion-long" }
+
+      it "links the completion to the proper directory" do
+        install_phase.call
+
+        expect(File).to be_identical full_target_path, full_source_path
+      end
+    end
+  end
+end
diff --git a/Library/Homebrew/test/cask/artifact/zshcompletion_spec.rb b/Library/Homebrew/test/cask/artifact/zshcompletion_spec.rb
new file mode 100644
index 0000000000..8a46f84f5e
--- /dev/null
+++ b/Library/Homebrew/test/cask/artifact/zshcompletion_spec.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+RSpec.describe Cask::Artifact::ZshCompletion, :cask do
+  let(:cask) { Cask::CaskLoader.load(cask_token) }
+
+  context "with install" do
+    let(:install_phase) do
+      lambda do
+        cask.artifacts.select { |a| a.is_a?(described_class) }.each do |artifact|
+          artifact.install_phase(command: NeverSudoSystemCommand, force: false)
+        end
+      end
+    end
+
+    let(:source_path) { cask.staged_path.join("_test") }
+    let(:target_path) { cask.config.zsh_completion.join("_test") }
+    let(:full_source_path) { cask.staged_path.join("test.zsh-completion") }
+    let(:full_target_path) { cask.config.zsh_completion.join("_test") }
+
+    before do
+      InstallHelper.install_without_artifacts(cask)
+    end
+
+    context "with completion" do
+      let(:cask_token) { "with-shellcompletion" }
+
+      it "links the completion to the proper directory" do
+        install_phase.call
+
+        expect(File).to be_identical target_path, source_path
+      end
+    end
+
+    context "with long completion" do
+      let(:cask_token) { "with-shellcompletion-long" }
+
+      it "links the completion to the proper directory" do
+        install_phase.call
+
+        expect(File).to be_identical full_target_path, full_source_path
+      end
+    end
+  end
+end
diff --git a/Library/Homebrew/test/support/fixtures/cask/AppWithShellCompletion.zip b/Library/Homebrew/test/support/fixtures/cask/AppWithShellCompletion.zip
new file mode 100644
index 0000000000..bd3496ae41
Binary files /dev/null and b/Library/Homebrew/test/support/fixtures/cask/AppWithShellCompletion.zip differ
diff --git a/Library/Homebrew/test/support/fixtures/cask/Casks/with-shellcompletion-long.rb b/Library/Homebrew/test/support/fixtures/cask/Casks/with-shellcompletion-long.rb
new file mode 100644
index 0000000000..8a0e80ad30
--- /dev/null
+++ b/Library/Homebrew/test/support/fixtures/cask/Casks/with-shellcompletion-long.rb
@@ -0,0 +1,11 @@
+cask "with-shellcompletion-long" do
+  version "1.2.3"
+  sha256 "957978d9b30adfda8e1f914ba8c8019e016545c8f7e16c6ab0234d189fac8146"
+
+  url "file://#{TEST_FIXTURE_DIR}/cask/AppWithShellCompletion.zip"
+  homepage "https://brew.sh/with-autodetected-manpage-section"
+
+  bash_completion "test.bash-completion"
+  fish_completion "test.fish-completion"
+  zsh_completion "test.zsh-completion"
+end
diff --git a/Library/Homebrew/test/support/fixtures/cask/Casks/with-shellcompletion.rb b/Library/Homebrew/test/support/fixtures/cask/Casks/with-shellcompletion.rb
new file mode 100644
index 0000000000..54f518dd4c
--- /dev/null
+++ b/Library/Homebrew/test/support/fixtures/cask/Casks/with-shellcompletion.rb
@@ -0,0 +1,11 @@
+cask "with-shellcompletion" do
+  version "1.2.3"
+  sha256 "957978d9b30adfda8e1f914ba8c8019e016545c8f7e16c6ab0234d189fac8146"
+
+  url "file://#{TEST_FIXTURE_DIR}/cask/AppWithShellCompletion.zip"
+  homepage "https://brew.sh/with-autodetected-manpage-section"
+
+  bash_completion "test.bash"
+  fish_completion "test.fish"
+  zsh_completion "_test"
+end