diff --git a/Library/Homebrew/test/bottle_api_spec.rb b/Library/Homebrew/test/bottle_api_spec.rb
new file mode 100644
index 0000000000..9be228e05a
--- /dev/null
+++ b/Library/Homebrew/test/bottle_api_spec.rb
@@ -0,0 +1,120 @@
+# typed: false
+# frozen_string_literal: true
+
+describe BottleAPI do
+  let(:bottle_json) {
+    <<~EOS
+      {
+        "name": "hello",
+        "pkg_version": "2.10",
+        "rebuild": 0,
+        "bottles": {
+          "arm64_big_sur": {
+            "url": "https://ghcr.io/v2/homebrew/core/hello/blobs/sha256:b3b083db0807ff92c6e289a298f378198354b7727fb9ba9f4d550b8e08f90a60"
+          },
+          "big_sur": {
+            "url": "https://ghcr.io/v2/homebrew/core/hello/blobs/sha256:69489ae397e4645127aa7773211310f81ebb6c99e1f8e3e22c5cdb55333f5408"
+          },
+          "x86_64_linux": {
+            "url": "https://ghcr.io/v2/homebrew/core/hello/blobs/sha256:e6980196298e0a9cfe4fa4e328a71a1869a4d5e1d31c38442150ed784cfc0e29"
+          }
+        },
+        "dependencies": []
+      }
+    EOS
+  }
+  let(:bottle_hash) { JSON.parse(bottle_json) }
+  let(:versions_json) {
+    <<~EOS
+      {
+        "foo":{"version":"1.2.3","revision":0},
+        "bar":{"version":"1.2","revision":4}
+      }
+    EOS
+  }
+
+  def mock_curl_output(stdout: "", success: true)
+    curl_output = OpenStruct.new(stdout: stdout, success?: success)
+    allow(Utils::Curl).to receive(:curl_output).and_return curl_output
+  end
+
+  describe "::fetch" do
+    it "fetches the bottle JSON for a formula that exists" do
+      mock_curl_output stdout: bottle_json
+      fetched_hash = described_class.fetch("foo")
+      expect(fetched_hash).to eq bottle_hash
+    end
+
+    it "raises an error if the formula does not exist" do
+      mock_curl_output success: false
+      expect { described_class.fetch("bar") }.to raise_error(ArgumentError, /No JSON file found/)
+    end
+
+    it "raises an error if the bottle JSON is invalid" do
+      mock_curl_output stdout: "foo"
+      expect { described_class.fetch("baz") }.to raise_error(ArgumentError, /Invalid JSON file/)
+    end
+  end
+
+  describe "::latest_pkg_version" do
+    it "returns the expected `PkgVersion` when the revision is 0" do
+      mock_curl_output stdout: versions_json
+      pkg_version = described_class.latest_pkg_version("foo")
+      expect(pkg_version.to_s).to eq "1.2.3"
+    end
+
+    it "returns the expected `PkgVersion` when the revision is not 0" do
+      mock_curl_output stdout: versions_json
+      pkg_version = described_class.latest_pkg_version("bar")
+      expect(pkg_version.to_s).to eq "1.2_4"
+    end
+
+    it "returns `nil` when the formula is not in the JSON file" do
+      mock_curl_output stdout: versions_json
+      pkg_version = described_class.latest_pkg_version("baz")
+      expect(pkg_version).to be_nil
+    end
+  end
+
+  describe "::bottle_available?" do
+    it "returns `true` if `fetch` succeeds" do
+      allow(described_class).to receive(:fetch)
+      expect(described_class.bottle_available?("foo")).to eq true
+    end
+
+    it "returns `false` if `fetch` fails" do
+      allow(described_class).to receive(:fetch).and_raise ArgumentError
+      expect(described_class.bottle_available?("foo")).to eq false
+    end
+  end
+
+  describe "::fetch_bottles" do
+    before do
+      allow(described_class).to receive(:fetch).and_return bottle_hash
+    end
+
+    it "fetches bottles if a bottle is available" do
+      allow(Utils::Bottles).to receive(:tag).and_return :arm64_big_sur
+      expect { described_class.fetch_bottles("hello") }.not_to raise_error
+    end
+
+    it "raises an error if no bottle is available" do
+      allow(Utils::Bottles).to receive(:tag).and_return :catalina
+      expect { described_class.fetch_bottles("hello") }.to raise_error(SystemExit)
+    end
+  end
+
+  describe "::checksum_from_url" do
+    let(:sha256) { "b3b083db0807ff92c6e289a298f378198354b7727fb9ba9f4d550b8e08f90a60" }
+    let(:url) { "https://ghcr.io/v2/homebrew/core/hello/blobs/sha256:#{sha256}" }
+    let(:non_ghp_url) { "https://formulae.brew.sh/api/formula/hello.json" }
+
+    it "returns the `sha256` for a GitHub packages URL" do
+      expect(described_class.checksum_from_url(url)).to eq sha256
+    end
+
+    it "returns `nil` for a non-GitHub packages URL" do
+      expect(described_class.checksum_from_url(non_ghp_url)).to be_nil
+    end
+  end
+end