diff --git a/packages/caip/src/caips/caip-19.test.ts b/packages/caip/src/caips/caip-19.test.ts
new file mode 100644
index 0000000..65ded2c
--- /dev/null
+++ b/packages/caip/src/caips/caip-19.test.ts
@@ -0,0 +1,164 @@
+import { describe, expect, it } from "vitest"
+
+import {
+  caip19AssetIdRegex,
+  caip19AssetNameRegex,
+  caip19AssetNamespaceRegex,
+  caip19AssetReferenceRegex,
+  caip19AssetTypeRegex,
+  caip19TokenIdRegex,
+} from "./index"
+
+describe("caip19AssetNamespaceRegex", () => {
+  it("matches a valid asset namespace", () => {
+    expect(caip19AssetNamespaceRegex.test("erc20")).toBe(true)
+  })
+
+  it("matches a namespace with hyphens", () => {
+    expect(caip19AssetNamespaceRegex.test("erc-20")).toBe(true)
+  })
+
+  it("rejects a namespace shorter than 3 characters", () => {
+    expect(caip19AssetNamespaceRegex.test("ab")).toBe(false)
+  })
+
+  it("rejects a namespace longer than 8 characters", () => {
+    expect(caip19AssetNamespaceRegex.test("abcdefghi")).toBe(false)
+  })
+
+  it("rejects uppercase characters", () => {
+    expect(caip19AssetNamespaceRegex.test("ERC20")).toBe(false)
+  })
+})
+
+describe("caip19AssetReferenceRegex", () => {
+  it("matches a contract address", () => {
+    expect(
+      caip19AssetReferenceRegex.test(
+        "0xdAC17F958D2ee523a2206206994597C13D831ec7",
+      ),
+    ).toBe(true)
+  })
+
+  it("matches a reference with dots and percent signs", () => {
+    expect(caip19AssetReferenceRegex.test("token.ref%20")).toBe(true)
+  })
+
+  it("rejects an empty reference", () => {
+    expect(caip19AssetReferenceRegex.test("")).toBe(false)
+  })
+
+  it("rejects a reference longer than 128 characters", () => {
+    const longRef = "a".repeat(129)
+    expect(caip19AssetReferenceRegex.test(longRef)).toBe(false)
+  })
+})
+
+describe("caip19AssetNameRegex", () => {
+  it("matches a valid ERC-20 asset name", () => {
+    expect(
+      caip19AssetNameRegex.test(
+        "erc20:0xdAC17F958D2ee523a2206206994597C13D831ec7",
+      ),
+    ).toBe(true)
+  })
+
+  it("matches a valid ERC-721 asset name", () => {
+    expect(
+      caip19AssetNameRegex.test(
+        "erc721:0xBC4CA0EdA7647A8aB7C2061c2E118A18a936f13D",
+      ),
+    ).toBe(true)
+  })
+
+  it("rejects an asset name without a colon separator", () => {
+    expect(caip19AssetNameRegex.test("erc20-0xabc")).toBe(false)
+  })
+})
+
+describe("caip19AssetTypeRegex", () => {
+  it("matches a valid ERC-20 asset type", () => {
+    expect(
+      caip19AssetTypeRegex.test(
+        "eip155:1/erc20:0xdAC17F958D2ee523a2206206994597C13D831ec7",
+      ),
+    ).toBe(true)
+  })
+
+  it("matches a valid asset type on Base", () => {
+    expect(
+      caip19AssetTypeRegex.test(
+        "eip155:8453/erc20:0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
+      ),
+    ).toBe(true)
+  })
+
+  it("rejects an asset type missing the chain ID", () => {
+    expect(
+      caip19AssetTypeRegex.test(
+        "erc20:0xdAC17F958D2ee523a2206206994597C13D831ec7",
+      ),
+    ).toBe(false)
+  })
+
+  it("rejects an asset type with an invalid namespace", () => {
+    expect(
+      caip19AssetTypeRegex.test(
+        "XX:1/erc20:0xdAC17F958D2ee523a2206206994597C13D831ec7",
+      ),
+    ).toBe(false)
+  })
+})
+
+describe("caip19TokenIdRegex", () => {
+  it("matches a numeric token ID", () => {
+    expect(caip19TokenIdRegex.test("1234")).toBe(true)
+  })
+
+  it("matches an alphanumeric token ID", () => {
+    expect(caip19TokenIdRegex.test("token-1.2")).toBe(true)
+  })
+
+  it("rejects an empty token ID", () => {
+    expect(caip19TokenIdRegex.test("")).toBe(false)
+  })
+
+  it("rejects a token ID longer than 78 characters", () => {
+    const longId = "a".repeat(79)
+    expect(caip19TokenIdRegex.test(longId)).toBe(false)
+  })
+})
+
+describe("caip19AssetIdRegex", () => {
+  it("matches a valid ERC-721 asset ID with token ID", () => {
+    expect(
+      caip19AssetIdRegex.test(
+        "eip155:1/erc721:0xBC4CA0EdA7647A8aB7C2061c2E118A18a936f13D/1234",
+      ),
+    ).toBe(true)
+  })
+
+  it("matches a valid asset ID on Arbitrum", () => {
+    expect(
+      caip19AssetIdRegex.test(
+        "eip155:42161/erc721:0xabc123def456abc123def456abc123def456abc1/99",
+      ),
+    ).toBe(true)
+  })
+
+  it("rejects an asset ID without a token ID", () => {
+    expect(
+      caip19AssetIdRegex.test(
+        "eip155:1/erc721:0xBC4CA0EdA7647A8aB7C2061c2E118A18a936f13D",
+      ),
+    ).toBe(false)
+  })
+
+  it("rejects an asset ID with an invalid chain namespace", () => {
+    expect(
+      caip19AssetIdRegex.test(
+        "XX:1/erc721:0xBC4CA0EdA7647A8aB7C2061c2E118A18a936f13D/1234",
+      ),
+    ).toBe(false)
+  })
+})
diff --git a/packages/caip/src/caips/caip-2.test.ts b/packages/caip/src/caips/caip-2.test.ts
new file mode 100644
index 0000000..991b657
--- /dev/null
+++ b/packages/caip/src/caips/caip-2.test.ts
@@ -0,0 +1,127 @@
+import { describe, expect, it } from "vitest"
+
+import {
+  caip2ChainIdRegex,
+  caip2ChainIds,
+  caip2NamespaceRegex,
+  caip2Parts,
+  caip2ReferenceRegex,
+} from "./index"
+
+describe("caip2Parts", () => {
+  it("parses a valid EIP-155 chain ID", () => {
+    const result = caip2Parts("eip155:1")
+    expect(result).toEqual({ namespace: "eip155", reference: "1" })
+  })
+
+  it("parses a valid Solana chain ID", () => {
+    const result = caip2Parts("solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp")
+    expect(result).toEqual({
+      namespace: "solana",
+      reference: "5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
+    })
+  })
+
+  it("throws for an empty string", () => {
+    expect(() => caip2Parts("" as `${string}:${string}`)).toThrow(
+      "Invalid CAIP-2 chain ID",
+    )
+  })
+
+  it("throws for a string without a colon", () => {
+    expect(() => caip2Parts("eip155" as `${string}:${string}`)).toThrow(
+      "Invalid CAIP-2 chain ID",
+    )
+  })
+
+  it("throws when the reference is missing after the colon", () => {
+    expect(() => caip2Parts("eip155:" as `${string}:${string}`)).toThrow(
+      "Invalid CAIP-2 chain ID",
+    )
+  })
+})
+
+describe("caip2ChainIdRegex", () => {
+  it("matches a valid EIP-155 chain ID", () => {
+    expect(caip2ChainIdRegex.test("eip155:1")).toBe(true)
+  })
+
+  it("matches a valid Solana chain ID", () => {
+    expect(
+      caip2ChainIdRegex.test("solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp"),
+    ).toBe(true)
+  })
+
+  it("matches a chain ID with hyphens and underscores in reference", () => {
+    expect(caip2ChainIdRegex.test("abc:ref_with-chars")).toBe(true)
+  })
+
+  it("rejects a namespace shorter than 3 characters", () => {
+    expect(caip2ChainIdRegex.test("ab:1")).toBe(false)
+  })
+
+  it("rejects a namespace longer than 8 characters", () => {
+    expect(caip2ChainIdRegex.test("abcdefghi:1")).toBe(false)
+  })
+
+  it("rejects uppercase characters in namespace", () => {
+    expect(caip2ChainIdRegex.test("EIP155:1")).toBe(false)
+  })
+
+  it("rejects an empty reference", () => {
+    expect(caip2ChainIdRegex.test("eip155:")).toBe(false)
+  })
+
+  it("rejects a reference longer than 32 characters", () => {
+    const longRef = "a".repeat(33)
+    expect(caip2ChainIdRegex.test(`eip155:${longRef}`)).toBe(false)
+  })
+
+  it("rejects a chain ID without a colon", () => {
+    expect(caip2ChainIdRegex.test("eip1551")).toBe(false)
+  })
+})
+
+describe("caip2NamespaceRegex", () => {
+  it("matches a valid namespace", () => {
+    expect(caip2NamespaceRegex.test("eip155")).toBe(true)
+  })
+
+  it("rejects a namespace with uppercase letters", () => {
+    expect(caip2NamespaceRegex.test("EIP155")).toBe(false)
+  })
+})
+
+describe("caip2ReferenceRegex", () => {
+  it("matches a numeric reference", () => {
+    expect(caip2ReferenceRegex.test("1")).toBe(true)
+  })
+
+  it("matches an alphanumeric reference with hyphens and underscores", () => {
+    expect(caip2ReferenceRegex.test("my_ref-123")).toBe(true)
+  })
+
+  it("rejects an empty reference", () => {
+    expect(caip2ReferenceRegex.test("")).toBe(false)
+  })
+})
+
+describe("caip2ChainIds", () => {
+  it("returns the correct Ethereum mainnet chain ID", () => {
+    expect(caip2ChainIds.ethereumMainnet).toBe("eip155:1")
+  })
+
+  it("returns the correct Base mainnet chain ID", () => {
+    expect(caip2ChainIds.baseMainnet).toBe("eip155:8453")
+  })
+
+  it("returns the correct Solana mainnet chain ID", () => {
+    expect(caip2ChainIds.solanaMainnet).toBe(
+      "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
+    )
+  })
+
+  it("returns the correct Arbitrum Sepolia chain ID", () => {
+    expect(caip2ChainIds.arbitrumSepolia).toBe("eip155:421614")
+  })
+})