Signer recognition issue (#735)

The use of `instanceof` operator leads to unexpected behaviors. The
issue has been solved with the use of built-in native check method.

What's more, implemented unit tests for functions that propagated the
issue described above.

typescript/src/lib/ethereum/index.ts

@@ -33,7 +33,7 @@ export async function ethereumNetworkFromSigner(
   signer: EthereumSigner
 ): Promise<EthereumNetwork> {
   let chainId: number
-  if (signer instanceof Signer) {
+  if (Signer.isSigner(signer)) {
     chainId = await signer.getChainId()
   } else {
     const network = await signer.getNetwork()
@@ -61,7 +61,7 @@ export async function ethereumNetworkFromSigner(
 export async function ethereumAddressFromSigner(
   signer: EthereumSigner
 ): Promise<EthereumAddress | undefined> {
-  if (signer instanceof Signer) {
+  if (Signer.isSigner(signer)) {
     return EthereumAddress.from(await signer.getAddress())
   } else {
     return undefined

typescript/test/lib/ethereum.test.ts

@@ -4,14 +4,16 @@ import {
   EthereumAddress,
   EthereumBridge,
   EthereumTBTCToken,
+  ethereumAddressFromSigner,
+  ethereumNetworkFromSigner,
   Hex,
 } from "../../src"
 import {
   deployMockContract,
   MockContract,
 } from "@ethereum-waffle/mock-contract"
 import chai, { assert, expect } from "chai"
-import { BigNumber, Wallet, constants, utils } from "ethers"
+import { BigNumber, Wallet, constants, getDefaultProvider, utils } from "ethers"
 import { abi as BridgeABI } from "@keep-network/tbtc-v2/artifacts/Bridge.json"
 import { abi as TBTCTokenABI } from "@keep-network/tbtc-v2/artifacts/TBTC.json"
 import { abi as WalletRegistryABI } from "@keep-network/ecdsa/artifacts/WalletRegistry.json"
@@ -591,4 +593,40 @@ describe("Ethereum", () => {
       })
     })
   })
+
+  describe("ethereumAddressFromSigner", () => {
+    context("when the signer is a wallet", () => {
+      const [mockSigner] = new MockProvider().getWallets()
+      it("should return the signer's address", async () => {
+        expect(await ethereumAddressFromSigner(mockSigner)).to.be.eql(
+          EthereumAddress.from(mockSigner.address)
+        )
+      })
+    })
+
+    context("when the signer is a provider", () => {
+      const mockProvider = getDefaultProvider()
+      it("should return undefined", async () => {
+        expect(await ethereumAddressFromSigner(mockProvider)).to.be.undefined
+      })
+    })
+  })
+
+  describe("ethereumNetworkFromSigner", () => {
+    context("when the signer is a wallet", () => {
+      const [mockSigner] = new MockProvider().getWallets()
+      it("should return the signer's network", async () => {
+        expect(await ethereumNetworkFromSigner(mockSigner)).to.be.eql("local")
+      })
+    })
+
+    context("when the signer is a provider", () => {
+      const mockProvider = getDefaultProvider()
+      it("should return the signer's network", async () => {
+        expect(await ethereumNetworkFromSigner(mockProvider)).to.be.eql(
+          "mainnet"
+        )
+      })
+    })
+  })
 })