fix(test): disable Anvil interval mining when batching txs in one block

Anvil runs with --block-time 1, so blocks keep getting mined even
with evm_setAutomine(false). Use evm_setIntervalMining(0) to fully
pause block production, then restore both after mining.

Author: Eikix

test-suite/e2e/test/encryptedERC20/EncryptedERC20.HCU.ts

@@ -137,6 +137,8 @@ describe('EncryptedERC20:HCU', function () {
     });
 
     afterEach(async function () {
+      // Restore both automine and 1-second interval mining (Anvil --block-time 1)
+      await ethers.provider.send('evm_setIntervalMining', [1]);
       await ethers.provider.send('evm_setAutomine', [true]);
     });
 
@@ -155,11 +157,14 @@ describe('EncryptedERC20:HCU', function () {
       expect(meter1).to.be.greaterThan(meter0);
 
       // Two txs batched in same block — meter must exceed the single-tx reading
+      // Disable both automine and interval mining (Anvil --block-time 1)
+      await ethers.provider.send('evm_setIntervalMining', [0]);
       await ethers.provider.send('evm_setAutomine', [false]);
       const txA = await sendEncryptedTransfer(this, 'alice', this.signers.bob.address, 100);
       const txB = await sendEncryptedTransfer(this, 'bob', this.signers.alice.address, 100);
       await ethers.provider.send('evm_mine');
       await ethers.provider.send('evm_setAutomine', [true]);
+      await ethers.provider.send('evm_setIntervalMining', [1]);
       const [receiptA, receiptB] = await Promise.all([txA.wait(), txB.wait()]);
       expect(receiptA?.status).to.eq(1);
       expect(receiptB?.status).to.eq(1);
@@ -210,6 +215,7 @@ describe('EncryptedERC20:HCU', function () {
         await mintAndDistribute(this);
 
         await mineNBlocks(1);
+        await ethers.provider.send('evm_setIntervalMining', [0]);
         await ethers.provider.send('evm_setAutomine', [false]);
 
         // Alice fills the cap, Bob would push block total over — use fixed gasLimit
@@ -219,6 +225,7 @@ describe('EncryptedERC20:HCU', function () {
 
         await ethers.provider.send('evm_mine');
         await ethers.provider.send('evm_setAutomine', [true]);
+        await ethers.provider.send('evm_setIntervalMining', [1]);
 
         const receipt1 = await tx1.wait();
         expect(receipt1?.status).to.eq(1, 'First transfer should succeed');
@@ -234,13 +241,15 @@ describe('EncryptedERC20:HCU', function () {
 
         // Block N: alice fills the cap, bob gets blocked
         await mineNBlocks(1);
+        await ethers.provider.send('evm_setIntervalMining', [0]);
         await ethers.provider.send('evm_setAutomine', [false]);
 
         const txAlice = await sendEncryptedTransfer(this, 'alice', this.signers.carol.address, 100);
         const txBob = await sendEncryptedTransfer(this, 'bob', this.signers.carol.address, 100, { gasLimit: 1_000_000 });
 
         await ethers.provider.send('evm_mine');
         await ethers.provider.send('evm_setAutomine', [true]);
+        await ethers.provider.send('evm_setIntervalMining', [1]);
 
         const receiptAlice = await txAlice.wait();
         expect(receiptAlice?.status).to.eq(1, 'Alice should succeed');