OTPLike Compatibility Layer - Test Gap Analysis

This document tracks the differences between the original otplike test suite and the loom-otp compatibility test suite.

Summary

Test File	Original Tests	Loom-OTP Tests	Extra Tests	Coverage
process_test.clj	171	150	1	99%
gen_server_test.clj	115	113	0	98%
timer_test.clj	32	34	0	100%+
supervisor_test.clj	23	21	4	91%
gen_server_ns_test.clj	1	1	0	100%

Note: Tests that were added in loom-otp (not present in original otplike) have been moved to *_extra_test.clj files:

• process_extra_test.clj - 1 test for registered function
• supervisor_extra_test.clj - 4 tests for dynamic child management and restart behavior

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All Tests Passing

All implemented tests are now passing:

Ran 422 tests containing 933 assertions.
0 failures, 0 errors.

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Intentionally Disabled Tests

async-allows-parking (1 test)

Status: Commented out with #_

Reason: This test expects process/async to execute concurrently (like core.async go blocks). In loom-otp, async executes synchronously and immediately on the calling thread. This is by design:

• With virtual threads, blocking is cheap - no need for parking/go blocks
• Sequential execution within a process is maintained
• The process mailbox can be accessed from within async blocks

The test was:

#_(deftest ^:parallel async-allows-parking
  (let [done (promise)
        done1 (promise)]
    (process/async
      (if (deref done 50 nil)
        (deliver done1 true)
        (is false "timeout")))
    (deliver done true)
    (await-completion!! done1 50)))

This test assumed the async body would run concurrently, allowing (deliver done true) to execute before the async body checks done. With synchronous execution, the async body runs first and times out.

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Intentionally Empty Stubs (Same as original otplike)

These tests are included as empty stubs from the original otplike. They represent edge cases that were never implemented in the original and are intentionally left as stubs in loom-otp for parity.

Category: exiting-process tests (10 empty stubs)

These test behavior when functions are called by an exiting process:

• self-fails-when-process-is-exiting
• exit-fails-when-called-by-exiting-process
• flag-fails-when-called-by-exiting-process
• link-fails-when-called-by-exiting-process
• monitor-fails-when-called-by-exiting-process
• demonitor-fails-when-called-by-exiting-process
• receive!-fails-when-called-by-exiting-process
• selective-receive!-fails-when-called-by-exiting-process
• spawn-link-fails-when-called-by-exiting-process
• unlink-fails-when-called-by-exiting-process

Category: Exhaustive strategy tests (3 empty stubs)

These are property-based exhaustive tests that would require substantial helper functions:

• test-one-for-one
• test-one-for-all
• test-rest-for-one

Category: Commented-out TODO tests from original

These were commented out in the original and remain as comments:

• exit-self-reason-is-process-exit-reason
• exit-kill-does-not-propagate
• process-killed-when-inbox-is-overflowed
• process-exit-reason-is-proc-fn-return-value
• spawned-process-available-from-within-process-by-reg-name
• there-are-no-residue-of-process-after-proc-fun-throws

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Extra Tests (loom-otp additions)

The following tests were added in loom-otp and are NOT present in the original otplike test suite. They have been moved to *_extra_test.clj files:

process_extra_test.clj

• registered-returns-registered-names - Tests registered function behavior

supervisor_extra_test.clj

• one-for-one--child-restart - Tests supervisor restart behavior
• start-child--adds-child - Tests dynamic child addition
• terminate-child--stops-child - Tests child termination
• restart-child--restarts-stopped-child - Tests manual child restart

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Function Availability in loom-otp

loom-otp.otplike.process

• process-info - YES
• processes - YES
• registered - YES
• await! - YES (macro)
• await!! - YES
• await?! - YES (macro)
• async - YES (executes synchronously, not concurrently like otplike)

loom-otp.otplike.gen-server

• start-ns! - YES

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Implementation Notes

Async/Await Semantics

In the original otplike, async used core.async go blocks:

(defmacro async [& body]
  `(->Async (go (ex-catch [:ok (do ~@body)])) nil []))

In loom-otp, async executes immediately and synchronously:

(defmacro async [& body]
  `(let [creator-pid# (core/try-self)
         result# (try
                   [:value (do ~@body)]
                   (catch InterruptedException ie#
                     (throw ie#))
                   (catch Throwable t#
                     [:exception (pexit/ex->reason t#)]))]
     (Async. (atom result#) [] creator-pid#)))

This change was made because:

1. Virtual threads make blocking cheap - no need for go block concurrency
2. Sequential execution within a process must be maintained for mailbox access
3. The gen_server implementation uses process operations inside async blocks

Timer Module

All timer functions have proper argument validation and process context checks.

Receive Macros

Both receive! and selective-receive! validate that at least one message pattern is provided.

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Notes

• Tests in loom-otp use promise instead of core.async/chan
• Tests in loom-otp use mount.lite for fixtures
• Virtual threads don't "park" like core.async go blocks - they block the virtual thread instead