test(minter): replace the stubbed runtime with a mockall mock of inter-canister calls

[gregorydemay]

TestCanisterRuntime answered inter-canister calls with a StubRuntime: an ordered queue of Candid-encoded responses that ignored which method was called and with which arguments. To assert what was sent, the mint tests additionally wrapped it in a RecordingStubRuntime and compared the recorded arguments after the fact.

Both are replaced by a mockall mock. Every test registers the calls it expects upfront, stating the canister, the method, the arguments, the attached cycles and the response — e.g. which signature a getTransaction call queries, which address a getBalance call reads, or the full icrc1_transfer arguments of a pending mint, including the created_at_time the ledger deduplicates retries on. A sendTransaction expectation matches the submitted transaction by its first signature, i.e. by the fee payer's signature. Each expectation answers exactly one matching call: a call without a matching expectation and an expectation that goes unused both fail the test, which already uncovered one test that queued a recent block the code under test never fetches.

The mockall mock is written against a Candid-erased copy of the Runtime trait because mockall cannot mock its generic methods directly (expectations need 'static generic parameters, which the trait does not require). Failure messages still print the arguments as readable Candid text. The builder style of TestCanisterRuntime (add_recent_block, transaction_builder, ...) is kept, so tests keep reading as a list of expected calls.

🤖 Generated with Claude Code

[Copilot]

Copilot review overview

🟢 Approval recommended

The test-only migration is internally consistent and adds strict verification without identified regressions.

Review effort: Balanced
Findings: None

What changed in this PR

Replaces queue-based inter-canister stubs with argument-aware mockall expectations, making minter tests validate canisters, methods, arguments, cycles, and call counts.

Changes:

• Adds a Candid-erased mock implementation of Runtime.
• Migrates RPC and ledger tests to explicit call expectations.
• Adds tests for matched, unexpected, and unused expectations.

File	Description
minter/​src/​test_fixtures/​runtime.rs	Implements inter-canister call mocking and expectation builders.
minter/​src/​test_fixtures/​tests.rs	Tests expectation matching and failure behavior.
minter/​src/​test_fixtures/​mod.rs	Updates fixture terminology.
minter/​src/​withdraw/​tests.rs	Validates withdrawal ledger and RPC calls.
minter/​src/​rpc/​tests.rs	Validates RPC arguments and submitted signatures.
minter/​src/​monitor/​tests.rs	Adds exact status-check and resubmission expectations.
minter/​src/​deposit/​sweep/​timer/​tests.rs	Validates failed sweep submission calls.
minter/​src/​deposit/​sweep/​tests.rs	Validates deposit-address balance queries.
minter/​src/​deposit/​sweep/​finalize/​tests.rs	Validates transaction lookup signatures.
minter/​src/​deposit/​manual/​tests.rs	Validates transaction lookups and ledger mint arguments.
minter/​src/​consolidate/​tests.rs	Migrates consolidation tests to transaction expectations.
minter/​Cargo.toml	Adds the test-only async trait dependency.
Cargo.lock	Records the minter dependency update.

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[Copilot]

Copilot review overview

🟢 Approval recommended

The mock replacement is coherent, comprehensively exercised, and all migrated tests use expectations consistent with production call construction.

Review effort: Balanced
Findings: None

[Copilot]

Copilot review overview

🟢 Approval recommended

The mock migration is consistent across affected tests and introduces strict validation without identified unresolved issues.

Review effort: Balanced
Findings: None

[Copilot]

Copilot review overview

🟢 Approval recommended

The test-only migration is coherent, complete, and preserves behavior while strengthening call validation.

Review effort: Balanced
Findings: None

[zeropath-ai]

✅ No security or compliance issues detected. Reviewed everything up to d5208e0.

Security Overview

• 🔎 Scanned files: 11 changed file(s)
• 🔗 Scan Link: https://zeropath.com/app/repositories/58f1cdfe-c0c2-41c1-8d28-3d6efcaf3266?scanId=61f1ff4f-f99f-43bb-95b1-18c3632c1003&codeScanTypes=PrScan&tab=issues&detectionTypes=traditional,businessLogic,customRule,IAC,SECRETS,CICD,EOL,uncategorized

Detected Code Changes

Change Type

Relevant files

Enhancement

► minter/src/deposit/sweep/finalize/tests.rs        Improve test stubs and expectations for transactions and balances ► minter/src/deposit/sweep/mint/tests.rs        Adjust minting tests to use richer runtime expectations and balance checks ► minter/src/deposit/sweep/tests.rs        Enhance deposit sweep tests with updated balance reads and address handling ► minter/src/deposit/sweep/timer/tests.rs        Update timer tests to expect specific transaction behavior ► minter/src/monitor/tests.rs        Refactor to use explicit expectations for balance/transaction status checks ► minter/src/rpc/tests.rs        Update RPC tests to use explicit get_balance/get_transaction expectations and remove some stub responses ► minter/src/rpc/tests.rs        Improve test scaffolding for balance/transaction RPC interactions

[Copilot]

🟡 Changes recommended

The mock update calls do not yield, preventing concurrent tests from modeling inter-canister await boundaries.

1 open finding

• Mock update calls must suspend before returning responses · New

🧠 Review effort: Balanced

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[Copilot]

🟢 Approval recommended

The mock replacement is consistently applied and preserves asynchronous call behavior while strengthening request verification.

0 open findings

1 resolved since last review

• Mock update calls must suspend before returning responses

🧠 Review effort: Balanced

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[Copilot]

🟢 Approval recommended

The test-only refactor consistently replaces ordered stubs with precise expectations and preserves asynchronous call behavior.

0 open findings

🧠 Review effort: Balanced

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