test: Minor test performance boost + before() hook (#5)

tests/assert-balances.ts

@@ -12,58 +12,57 @@ import BN from "bn.js";
 describe("assert-balances", () => {
   anchor.setProvider(anchor.Provider.env());
   const program = anchor.workspace.AssertBalances;
-  const mints: Array<MintAccounts> = [];
+  let mints: Array<MintAccounts>;
   let ctx;
 
-  it("BOILERPLATE: Setup token accounts", async () => {
-    // Iniitialize each mint and token for the test suite.
-    for (let k = 0; k < 5; k += 1) {
-      // Create mint.
-      const client = await Token.createMint(
-        program.provider.connection,
-        program.provider.wallet.payer,
-        program.provider.wallet.publicKey,
-        null,
-        6,
-        TOKEN_PROGRAM_ID
-      );
+  before(async () => {
+    // Initialize each mint and token for the test suite.
+    mints = await Promise.all(
+      [...Array(5)].map(async () => {
+        const client = await Token.createMint(
+          program.provider.connection,
+          program.provider.wallet.payer,
+          program.provider.wallet.publicKey,
+          null,
+          6,
+          TOKEN_PROGRAM_ID
+        );
 
-      // Create token account.
-      const tokenAddress = await client.createAccount(
-        program.provider.wallet.publicKey
-      );
+        // Create token account.
+        const tokenAddress = await client.createAccount(
+          program.provider.wallet.publicKey
+        );
 
-      // Mint to the account.
-      await client.mintTo(
-        tokenAddress,
-        program.provider.wallet.payer,
-        [],
-        1000000
-      );
+        // Mint to the account.
+        await client.mintTo(
+          tokenAddress,
+          program.provider.wallet.payer,
+          [],
+          1000000
+        );
 
-      // Get the account data.
-      const tokenAccount = await client.getAccountInfo(tokenAddress);
+        // Get the account data.
+        const tokenAccount = await client.getAccountInfo(tokenAddress);
 
-      // Save the mints.
-      mints.push({
-        client,
-        tokenAddress,
-        tokenAccount,
-      });
-    }
+        // Save the mints.
+        return {
+          client,
+          tokenAddress,
+          tokenAccount,
+        };
+      })
+    );
 
     // Shared context for subsequent instructions.
     ctx = {
       accounts: {
         user: program.provider.wallet.publicKey,
       },
-      remainingAccounts: mints.map((m) => {
-        return {
-          pubkey: m.tokenAddress,
-          isWritable: false,
-          isSigner: false,
-        };
-      }),
+      remainingAccounts: mints.map((m) => ({
+        pubkey: m.tokenAddress,
+        isWritable: false,
+        isSigner: false,
+      })),
     };
   });
 
@@ -116,7 +115,7 @@ const assertRejectsWithCode = (expectedCode: number) => async (rpcInvocation) =>
     async () => {
       await rpcInvocation();
     },
-    (err: { code: number }) => {
+    (err: { code: number; msg: string }) => {
       assert.equal(err.code, expectedCode);
       return true;
     }