diff --git a/Library/Homebrew/test/shell_test.rb b/Library/Homebrew/test/shell_test.rb
deleted file mode 100644
index 9704897028..0000000000
--- a/Library/Homebrew/test/shell_test.rb
+++ /dev/null
@@ -1,56 +0,0 @@
-require "testing_env"
-require "utils/shell"
-
-class ShellSmokeTest < Homebrew::TestCase
-  def test_path_to_shell
-    # raw command name
-    assert_equal :bash, Utils::Shell.path_to_shell("bash")
-    # full path
-    assert_equal :bash, Utils::Shell.path_to_shell("/bin/bash")
-    # versions
-    assert_equal :zsh, Utils::Shell.path_to_shell("zsh-5.2")
-    # strip newline too
-    assert_equal :zsh, Utils::Shell.path_to_shell("zsh-5.2\n")
-  end
-
-  def test_path_to_shell_failure
-    assert_nil Utils::Shell.path_to_shell("")
-    assert_nil Utils::Shell.path_to_shell("@@@@@@")
-    assert_nil Utils::Shell.path_to_shell("invalid_shell-4.2")
-  end
-
-  def test_sh_quote
-    assert_equal "''", Utils::Shell.sh_quote("")
-    assert_equal "\\\\", Utils::Shell.sh_quote("\\")
-    assert_equal "'\n'", Utils::Shell.sh_quote("\n")
-    assert_equal "\\$", Utils::Shell.sh_quote("$")
-    assert_equal "word", Utils::Shell.sh_quote("word")
-  end
-
-  def test_csh_quote
-    assert_equal "''", Utils::Shell.csh_quote("")
-    assert_equal "\\\\", Utils::Shell.csh_quote("\\")
-    # note this test is different than for sh
-    assert_equal "'\\\n'", Utils::Shell.csh_quote("\n")
-    assert_equal "\\$", Utils::Shell.csh_quote("$")
-    assert_equal "word", Utils::Shell.csh_quote("word")
-  end
-
-  def prepend_path_shell(shell, path, fragment)
-    ENV["SHELL"] = shell
-
-    prepend_message = Utils::Shell.prepend_path_in_shell_profile(path)
-    assert(
-      prepend_message.start_with?(fragment),
-      "#{shell}: expected #{prepend_message} to match #{fragment}",
-    )
-  end
-
-  def test_prepend_path_in_shell_profile
-    prepend_path_shell "/bin/tcsh", "/path", "echo 'setenv PATH /path"
-
-    prepend_path_shell "/bin/bash", "/path", "echo 'export PATH=\"/path"
-
-    prepend_path_shell "/usr/local/bin/fish", "/path", "echo 'set -g fish_user_paths \"/path\" $fish_user_paths' >>"
-  end
-end
diff --git a/Library/Homebrew/test/utils/shell_spec.rb b/Library/Homebrew/test/utils/shell_spec.rb
new file mode 100644
index 0000000000..c44bd82533
--- /dev/null
+++ b/Library/Homebrew/test/utils/shell_spec.rb
@@ -0,0 +1,93 @@
+require "utils/shell"
+
+describe Utils::Shell do
+  describe "::shell_profile" do
+    it "returns ~/.bash_profile by default" do
+      ENV["SHELL"] = "/bin/another_shell"
+      expect(subject.shell_profile).to eq("~/.bash_profile")
+    end
+
+    it "returns ~/.bash_profile for Sh" do
+      ENV["SHELL"] = "/bin/another_shell"
+      expect(subject.shell_profile).to eq("~/.bash_profile")
+    end
+
+    it "returns ~/.bash_profile for Bash" do
+      ENV["SHELL"] = "/bin/bash"
+      expect(subject.shell_profile).to eq("~/.bash_profile")
+    end
+
+    it "returns ~/.zshrc for Zsh" do
+      ENV["SHELL"] = "/bin/zsh"
+      expect(subject.shell_profile).to eq("~/.zshrc")
+    end
+
+    it "returns ~/.kshrc for Ksh" do
+      ENV["SHELL"] = "/bin/ksh"
+      expect(subject.shell_profile).to eq("~/.kshrc")
+    end
+  end
+
+  describe "::path_to_shell" do
+    it "supports a raw command name" do
+      expect(subject.path_to_shell("bash")).to eq(:bash)
+    end
+
+    it "supports full paths" do
+      expect(subject.path_to_shell("/bin/bash")).to eq(:bash)
+    end
+
+    it "supports versions" do
+      expect(subject.path_to_shell("zsh-5.2")).to eq(:zsh)
+    end
+
+    it "strips newlines" do
+      expect(subject.path_to_shell("zsh-5.2\n")).to eq(:zsh)
+    end
+
+    it "returns nil when input is invalid" do
+      expect(subject.path_to_shell("")).to be nil
+      expect(subject.path_to_shell("@@@@@@")).to be nil
+      expect(subject.path_to_shell("invalid_shell-4.2")).to be nil
+    end
+  end
+
+  specify "::sh_quote" do
+    expect(subject.sh_quote("")).to eq("''")
+    expect(subject.sh_quote("\\")).to eq("\\\\")
+    expect(subject.sh_quote("\n")).to eq("'\n'")
+    expect(subject.sh_quote("$")).to eq("\\$")
+    expect(subject.sh_quote("word")).to eq("word")
+  end
+
+  specify "::csh_quote" do
+    expect(subject.csh_quote("")).to eq("''")
+    expect(subject.csh_quote("\\")).to eq("\\\\")
+    # note this test is different than for sh
+    expect(subject.csh_quote("\n")).to eq("'\\\n'")
+    expect(subject.csh_quote("$")).to eq("\\$")
+    expect(subject.csh_quote("word")).to eq("word")
+  end
+
+  describe "::prepend_path_in_shell_profile" do
+    let(:path) { "/my/path" }
+
+    it "supports Tcsh" do
+      ENV["SHELL"] = "/bin/tcsh"
+      expect(subject.prepend_path_in_shell_profile(path))
+        .to start_with("echo 'setenv PATH #{path}:$")
+    end
+
+    it "supports Bash" do
+      ENV["SHELL"] = "/bin/bash"
+      expect(subject.prepend_path_in_shell_profile(path))
+        .to start_with("echo 'export PATH=\"#{path}:$")
+    end
+
+    it "supports Fish" do
+      ENV["SHELL"] = "/usr/local/bin/fish"
+      expect(subject.prepend_path_in_shell_profile(path))
+        .to start_with("echo 'set -g fish_user_paths \"#{path}\" $fish_user_paths' >>")
+    end
+  end
+end