feat: L2Provider test scaffold

packages/sdk/test/l2-provider.spec.ts

+/* eslint-disable @typescript-eslint/no-empty-function */
+import './setup'
+
+describe('L2Provider', () => {
+  describe('getL1GasPrice', () => {
+    it('should query the GasPriceOracle contract', () => {})
+  })
+
+  describe('estimateL1Gas', () => {
+    it('should query the GasPriceOracle contract', () => {})
+  })
+
+  describe('estimateL1GasCost', () => {
+    it('should multiply the estimated L1 gas cost by the L1 gas price', () => {})
+  })
+
+  describe('estimateL2GasCost', () => {
+    it('should multiply the estimated L2 gas cost by the L1 gas price', () => {})
+  })
+
+  describe('estimateTotalGasCost', () => {
+    it('should be the sum of the L1 and L2 gas cost estimates', () => {})
+  })
+})