diff --git a/test/GasPriceOracle.test.ts b/test/GasPriceOracle.test.ts
new file mode 100644
index 00000000..7a6fae91
--- /dev/null
+++ b/test/GasPriceOracle.test.ts
@@ -0,0 +1,61 @@
+// @note: This test is _not_ run automatically as part of git hooks or CI.
+import dotenv from "dotenv";
+import { providers } from "ethers";
+import { getGasPriceEstimate } from "../src/gasPriceOracle";
+import { BigNumber, bnZero, parseUnits } from "../src/utils";
+import { expect, makeCustomTransport } from "../test/utils";
+dotenv.config({ path: ".env" });
+
+const stdLastBaseFeePerGas = parseUnits("12", 9);
+const stdMaxPriorityFeePerGas = parseUnits("1", 9); // EIP-1559 chains only
+const chainIds = [1, 10, 137, 324, 8453, 42161, 534352];
+
+const customTransport = makeCustomTransport({ stdLastBaseFeePerGas, stdMaxPriorityFeePerGas });
+
+const provider = new providers.StaticJsonRpcProvider("https://eth.llamarpc.com");
+
+describe("Gas Price Oracle", function () {
+  it("Gas Price Retrieval", async function () {
+    for (const chainId of chainIds) {
+      const chainKey = `NEW_GAS_PRICE_ORACLE_${chainId}`;
+      process.env[chainKey] = "true";
+      const { maxFeePerGas, maxPriorityFeePerGas } = await getGasPriceEstimate(provider, {
+        chainId,
+        transport: customTransport,
+      });
+
+      expect(BigNumber.isBigNumber(maxFeePerGas)).to.be.true;
+      expect(BigNumber.isBigNumber(maxPriorityFeePerGas)).to.be.true;
+
+      if (chainId === 137) {
+        // The Polygon gas station isn't mocked, so just ensure that the fees have a valid relationship.
+        expect(maxFeePerGas.gt(0)).to.be.true;
+        expect(maxPriorityFeePerGas.gt(0)).to.be.true;
+        expect(maxPriorityFeePerGas.lt(maxFeePerGas)).to.be.true;
+      } else if (chainId === 42161) {
+        // Arbitrum priority fees are refunded, so drop the priority fee from estimates.
+        // Expect a 1.2x multiplier on the last base fee.
+        expect(maxFeePerGas.eq(stdLastBaseFeePerGas.mul("120").div("100").add(1))).to.be.true;
+        expect(maxPriorityFeePerGas.eq(1)).to.be.true;
+      } else {
+        expect(maxFeePerGas.gt(bnZero)).to.be.true;
+        expect(maxPriorityFeePerGas.gt(bnZero)).to.be.true;
+      }
+
+      delete process.env[chainKey];
+    }
+  });
+  it("Ethers: applies markup to maxFeePerGas", async function () {
+    for (const chainId of chainIds) {
+      const { maxFeePerGas: markedUpMaxFeePerGas, maxPriorityFeePerGas: markedUpMaxPriorityFeePerGas } =
+        await getGasPriceEstimate(provider, { chainId, baseFeeMultiplier: 2, transport: customTransport });
+      const { maxFeePerGas, maxPriorityFeePerGas } = await getGasPriceEstimate(provider, {
+        chainId,
+        baseFeeMultiplier: 1,
+        transport: customTransport,
+      });
+      expect(markedUpMaxFeePerGas.gt(maxFeePerGas)).to.be.true;
+      expect(markedUpMaxPriorityFeePerGas).to.equal(maxPriorityFeePerGas);
+    }
+  });
+});