myxce/src/scheduler/testsuite/test_picker_wiring.c

/*
 * test_picker_wiring.c - white-box tests for wiring builtin_fcfs in as the
 * registered default picker and removing the hardcoded picker string
 * (scheduler-core spec, task 2.4, Req 1 AC 6, Req 2 AC 5, Req 3 AC 1).
 *
 * RED: before task 2.4, register_builtin_fcfs() did not exist (declared in
 * plugin.h but no body in builtin_fcfs.c) -- this file failed to link.
 * sched_resolve_job_picker() (schedobj.c, task 2.4) existed but nothing
 * had ever registered "builtin_fcfs" for it to find, so the "default
 * resolves to builtin_fcfs" half of this file's coverage could not pass;
 * sched_job_picker() (scheduler.c) still hardcoded "xce_sched_fcfs".
 * GREEN: register_builtin_fcfs() registers builtin_fcfs's native
 * xce_job_picker_iface_t under "builtin_fcfs" via the real plugin_register()
 * (job_elect_fn stays NULL -- no legacy-wrapper substitution);
 * sched_set_default_job_pick_plugin() + sched_resolve_job_picker() together
 * resolve an unset job_pick_plugin to the registered builtin_fcfs plugin; an
 * unregistered configured name fails resolution with -ENOENT (distinct from
 * -EINVAL for "registered but not a valid picker" and "unset name") rather
 * than silently falling back to anything.
 *
 * Scope note (this file does NOT drive sched_job_picker() itself): that
 * function is `static` in scheduler.c, which has a much larger external
 * dependency surface (xcecli_ctx_*, sel_register_alloc_thread, resource.c's
 * allocation path, decision.c's decision constructors, ...) than any other
 * white-box test in this directory pulls in -- no existing test #includes
 * scheduler.c directly (test.c only pulls in resource.c), and doing so here
 * would mean stubbing on the order of twenty external symbols this file's
 * tests would never actually exercise, just to satisfy the linker. Per the
 * task's own guidance to prefer a tractable direct test over spinning real
 * threads, this file instead directly tests the exact condition
 * sched_job_picker() branches on
 * (`job_picker->job_elect_fn != NULL` selects the legacy delegation path,
 * `== NULL` selects the generic picker_iface loop): resolving a
 * legacy-registered plugin (job_elect_fn set, no picker_iface of its own)
 * comes back with job_elect_fn non-NULL and picker_iface pointing at
 * plugin.c's legacy_picker_wrapper_iface (visible in this TU -- see below);
 * resolving builtin_fcfs comes back with job_elect_fn NULL and a fully
 * populated native picker_iface. That is the entire input the branch reads.
 *
 * #include's the real plugin.c, schedobj.c, and plugins/builtin_fcfs.c
 * (white-box, same convention as test_plugin_picker_registration.c /
 * test_picker_config_fields.c / test_picker_fcfs.c) so this test exercises
 * the real plugin_register(), the real sched_set_default_job_pick_plugin()/
 * sched_resolve_job_picker(), and the real register_builtin_fcfs() --  not a
 * re-implementation of any of them. No symbol name collisions exist between
 * the three files (verified: distinct static helper names throughout).
 */
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <tlog.h>
#include <unity/unity.h>

#include "kvmgr.h"
#include "scheduler.h"
#include "xstring.h"

/* ---------------------------------------------------------------------- */
/* Stubs for externs referenced by plugin.c/schedobj.c/builtin_fcfs.c that
 * are defined in other .c files not linked into this whole-file-#include
 * TU. None of this file's tests exercise these paths -- present only to
 * satisfy the linker, same stub set (minus plugin_job_update/
 * plugin_queue_update/plugin_job_rusage_update/plugin_prepare_allocation,
 * which the REAL plugin.c now provides in this TU) as
 * test_picker_config_fields.c uses for its own schedobj.c-only include.
 * ---------------------------------------------------------------------- */
/* sched_get_user/sched_get_project/sched_get_queue/sched_get_job/
 * sched_add_user/sched_add_project relocated to core.h (scheduler-core
 * spec, task 4.1) -- now operate on xce_sched_core_t*, not
 * xce_scheduler_t*. Kept as stubs here (not pulling in core.c's real
 * implementations): this file never exercises make_sched_job/queue
 * lookup, only picker registration/resolution. */
xce_sched_user_t* sched_get_user(xce_sched_core_t* s, char* n)
{
    (void)s;
    (void)n;
    return NULL;
}
xce_sched_project_t* sched_get_project(xce_sched_core_t* s, char* n)
{
    (void)s;
    (void)n;
    return NULL;
}
xce_sched_queue_t* sched_get_queue(xce_sched_core_t* s, char* n)
{
    (void)s;
    (void)n;
    return NULL;
}
xce_sched_job_t* sched_get_job(xce_sched_core_t* s, uint64_t jobid)
{
    (void)s;
    (void)jobid;
    return NULL;
}
xce_job_account_t* make_job_account(xce_job_alloc_t* a)
{
    (void)a;
    return NULL;
}
void free_job_account(xce_job_account_t* a) { (void)a; }
/* resource-accounting.md's reconciliation (resource.c, not linked here) --
 * link-satisfying stub only, same rationale as every other stub here. */
int sched_reconcile_job_resource_usage(xce_sched_core_t* c,
                                       xce_job_account_t* a,
                                       xce_job_rusages_t* r)
{
    (void)c; (void)a; (void)r; return 0;
}
int  sched_add_user(xce_sched_core_t* s, xce_sched_user_t* u)
{
    (void)s;
    (void)u;
    return 0;
}
int sched_add_project(xce_sched_core_t* s, xce_sched_project_t* p)
{
    (void)s;
    (void)p;
    return 0;
}
void sched_worker_release_host_ctx(xce_sched_worker_t* w) { (void)w; }

/* plugin.c's plugin_prepare_allocation() (a category unrelated to picker
 * resolution) calls this -- stub matching test_plugin_picker_registration.c's
 * own. */
int sched_fill_limit_requests(xce_scheduler_t* sched, xvec_idval_t* req,
                              xlist_t* limits)
{
    (void)sched;
    (void)req;
    (void)limits;
    return 0;
}

/* builtin_fcfs.c's next_job() (compiled into this TU even though this
 * file's tests never call it) calls these -- always-ready stub, same
 * convention as test_picker_fcfs.c. */
int sched_queue_is_ready(xce_sched_queue_t* q)
{
    (void)q;
    return 1;
}
int sched_job_is_ready(xce_sched_job_t* j)
{
    (void)j;
    return 1;
}

/* Pull in the real implementations under test. */
#include "../src/plugin.c"
#include "../src/plugins/builtin_fcfs.c"
#include "../src/schedobj.c"

void setUp(void) { return; }
void tearDown(void) { return; }

/* ---------------------------------------------------------------------- */
/* Fixture: a real sched->core.plugins kvmgr (same setup scheduler.c's
 * sched_plugin_init() uses) plus the xstring/CSE intern tables
 * sched_set_default_job_pick_plugin()'s makeString() call needs. Nothing is
 * torn down between tests (suite convention, ASAN_OPTIONS=detect_leaks=0). */
/* ---------------------------------------------------------------------- */
static void fixture_init(xce_scheduler_t* sched)
{
    kvmgr_params_t params = { .key_type   = KVMGR_KEY_STRING,
                              .nslots     = 16,
                              .delta      = 8,
                              .datakiller = plugin_unregister };

    memset(sched, 0, sizeof(*sched));
    resreq_init(1);
    xstring_table_init(1024 * 16);
    sched->core.plugins = makeInstance(&xkvmgr_type, &params);
    TEST_ASSERT_NOT_NULL(sched->core.plugins);
}

/* Minimal legacy (job_elect_fn-only) plugin, mirroring
 * test_plugin_picker_registration.c's legacy_plugin_init -- a standalone
 * stand-in for plugins/fcfs.c's actual shape, not a dependency on fcfs.c
 * itself. */
static void* legacy_job_elect_fn_stub(void* arg)
{
    (void)arg;
    return NULL;
}

static xce_sched_plugin_t* make_legacy_plugin(char* name)
{
    xce_sched_plugin_t* plugin
        = (xce_sched_plugin_t*)calloc(1, sizeof(*plugin));

    TEST_ASSERT_NOT_NULL(plugin);
    plugin->name         = name;
    plugin->job_elect_fn = (plugin_job_election_fn_t)legacy_job_elect_fn_stub;

    return plugin;
}

/* ---------------------------------------------------------------------- */
/* Req 3 AC 1: register_builtin_fcfs()                                    */
/* ---------------------------------------------------------------------- */

static void test_register_builtin_fcfs_registers_under_name_builtin_fcfs(void)
{
    xce_scheduler_t     sched;
    xce_sched_plugin_t* found = NULL;
    int                 rc;

    fixture_init(&sched);

    rc = register_builtin_fcfs(&sched);
    TEST_ASSERT_GREATER_OR_EQUAL(0, rc);

    lock(sched.core.plugins, RTTI_LOCK_READ);
    rc = key_find(sched.core.plugins, "builtin_fcfs", (void**)&found);
    unlock(sched.core.plugins);

    TEST_ASSERT_GREATER_THAN(0, rc);
    TEST_ASSERT_NOT_NULL(found);
    TEST_ASSERT_EQUAL_STRING("builtin_fcfs", found->name);
}

/* builtin_fcfs registers as a NATIVE picker: picker_iface non-NULL,
 * job_elect_fn NULL -- this is the exact input sched_job_picker()'s branch
 * condition reads (see this file's own header comment). Also confirms
 * every MUST hook from tasks 2.1-2.3 is wired, and on_config/on_job_rusage
 * are NULL per Req 3 AC 2's table. */
static void test_register_builtin_fcfs_is_native_not_legacy(void)
{
    xce_scheduler_t     sched;
    xce_sched_plugin_t* found = NULL;

    fixture_init(&sched);
    TEST_ASSERT_GREATER_OR_EQUAL(0, register_builtin_fcfs(&sched));

    lock(sched.core.plugins, RTTI_LOCK_READ);
    key_find(sched.core.plugins, "builtin_fcfs", (void**)&found);
    unlock(sched.core.plugins);

    TEST_ASSERT_NOT_NULL(found);
    TEST_ASSERT_NULL(found->job_elect_fn);
    TEST_ASSERT_NOT_NULL(found->picker_iface);
    TEST_ASSERT_EQUAL_PTR(builtin_fcfs_next_job, found->picker_iface->next_job);
    TEST_ASSERT_EQUAL_PTR(builtin_fcfs_begin_session,
                          found->picker_iface->begin_session);
    TEST_ASSERT_EQUAL_PTR(builtin_fcfs_end_session,
                          found->picker_iface->end_session);
    TEST_ASSERT_EQUAL_PTR(builtin_fcfs_on_dispatch,
                          found->picker_iface->on_dispatch);
    TEST_ASSERT_EQUAL_PTR(builtin_fcfs_on_pend, found->picker_iface->on_pend);
    TEST_ASSERT_EQUAL_PTR(builtin_fcfs_on_queue_update,
                          found->picker_iface->on_queue_update);
    TEST_ASSERT_EQUAL_PTR(builtin_fcfs_on_job_push,
                          found->picker_iface->on_job_push);
    TEST_ASSERT_EQUAL_PTR(builtin_fcfs_on_job_state_change,
                          found->picker_iface->on_job_state_change);
    TEST_ASSERT_EQUAL_PTR(builtin_fcfs_on_job_update,
                          found->picker_iface->on_job_update);
    TEST_ASSERT_NULL(found->picker_iface->on_config);
    TEST_ASSERT_NULL(found->picker_iface->on_job_rusage);
}

/* register_builtin_fcfs() wires init_fn/fini_fn adapters into the EXISTING
 * plugin_register()/plugin_unregister() call sites (see builtin_fcfs.c's
 * own comment on why) -- confirms init actually ran: plugin->data is
 * non-NULL immediately after registration, not left NULL until some other
 * call. */
static void test_register_builtin_fcfs_runs_init_via_init_fn_adapter(void)
{
    xce_scheduler_t     sched;
    xce_sched_plugin_t* found = NULL;

    fixture_init(&sched);
    TEST_ASSERT_GREATER_OR_EQUAL(0, register_builtin_fcfs(&sched));

    lock(sched.core.plugins, RTTI_LOCK_READ);
    key_find(sched.core.plugins, "builtin_fcfs", (void**)&found);
    unlock(sched.core.plugins);

    TEST_ASSERT_NOT_NULL(found);
    TEST_ASSERT_NOT_NULL(found->data);
}

/* ---------------------------------------------------------------------- */
/* Req 1 AC 6 / Req 2 AC 1 / Req 2 AC 5: default resolution + fail-loud    */
/* ---------------------------------------------------------------------- */

/* tasks.md Observable, half 1: "starting the scheduler with no picker
 * config uses builtin_fcfs automatically." */
static void test_unset_job_pick_plugin_resolves_to_builtin_fcfs_by_default(void)
{
    xce_scheduler_t     sched;
    xce_sched_plugin_t* resolved = NULL;
    int                 rc;

    fixture_init(&sched);
    TEST_ASSERT_GREATER_OR_EQUAL(0, register_builtin_fcfs(&sched));
    TEST_ASSERT_NULL(sched.core.job_pick_plugin);

    sched_set_default_job_pick_plugin(&sched);
    TEST_ASSERT_EQUAL_STRING("builtin_fcfs", sched.core.job_pick_plugin);

    rc = sched_resolve_job_picker(&sched.core, &resolved);

    TEST_ASSERT_EQUAL_INT(0, rc);
    TEST_ASSERT_NOT_NULL(resolved);
    TEST_ASSERT_EQUAL_STRING("builtin_fcfs", resolved->name);
    /* This is the exact condition sched_job_picker() (scheduler.c) branches
     * on: NULL job_elect_fn selects the generic picker_iface loop. */
    TEST_ASSERT_NULL(resolved->job_elect_fn);
    TEST_ASSERT_NOT_NULL(resolved->picker_iface);
}

/* tasks.md Observable, half 2: "starting it with an unregistered picker
 * name fails startup with a clear error instead of silently falling
 * back." -ENOENT specifically (distinct from -EINVAL below) --
 * sched_resolve_job_picker's documented contract (core.h). */
static void
test_unregistered_configured_name_fails_with_enoent_not_silent_fallback(void)
{
    xce_scheduler_t     sched;
    xce_sched_plugin_t* resolved = (xce_sched_plugin_t*)0x1; /* sentinel */
    int                 rc;

    fixture_init(&sched);
    TEST_ASSERT_GREATER_OR_EQUAL(0, register_builtin_fcfs(&sched));

    sched.core.job_pick_plugin = "totally_unregistered_picker_name";

    rc = sched_resolve_job_picker(&sched.core, &resolved);

    TEST_ASSERT_EQUAL_INT(-ENOENT, rc);
    /* Not a silent fallback to builtin_fcfs (still registered) or to
     * whatever the sentinel was -- *out is reset to NULL on any failure
     * path (schedobj.c's sched_resolve_job_picker, `*out = NULL;` up
     * front). */
    TEST_ASSERT_NULL(resolved);
}

/* A DIFFERENT failure mode than "not registered at all": the name IS
 * registered, but the registered plugin is neither a native picker nor a
 * legacy job_elect_fn plugin (e.g. today's limit/allocator categories) --
 * -EINVAL, not -ENOENT. Confirms the two failure modes are genuinely
 * distinguishable, not the same generic "no" collapsed into one code. */
static void test_registered_but_not_a_picker_fails_with_einval_not_enoent(void)
{
    xce_scheduler_t     sched;
    xce_sched_plugin_t* non_picker = NULL;
    xce_sched_plugin_t* resolved   = NULL;
    int                 rc;

    fixture_init(&sched);

    non_picker = (xce_sched_plugin_t*)calloc(1, sizeof(*non_picker));
    TEST_ASSERT_NOT_NULL(non_picker);
    non_picker->name = "not_a_picker";
    /* job_elect_fn and picker_iface both left NULL -- today's
     * allocator/limit plugin shape (register_fcfs's own sibling
     * categories), which plugin_register() leaves untouched (task 1.2). */
    TEST_ASSERT_GREATER_OR_EQUAL(0, plugin_register(&sched, non_picker));

    sched.core.job_pick_plugin = "not_a_picker";

    rc = sched_resolve_job_picker(&sched.core, &resolved);

    TEST_ASSERT_EQUAL_INT(-EINVAL, rc);
    TEST_ASSERT_NULL(resolved);
}

/* Unset job_pick_plugin, and the caller never called
 * sched_set_default_job_pick_plugin() either -- -EINVAL (scheduler.h's
 * documented contract), distinct from both cases above. */
static void
test_unset_job_pick_plugin_without_defaulting_fails_with_einval(void)
{
    xce_scheduler_t     sched;
    xce_sched_plugin_t* resolved = NULL;
    int                 rc;

    fixture_init(&sched);
    TEST_ASSERT_NULL(sched.core.job_pick_plugin);

    rc = sched_resolve_job_picker(&sched.core, &resolved);

    TEST_ASSERT_EQUAL_INT(-EINVAL, rc);
    TEST_ASSERT_NULL(resolved);
}

/* ---------------------------------------------------------------------- */
/* sched_job_picker()'s legacy-vs-native branch condition (scheduler.c) --
 * see this file's header comment for why this is tested at the resolved-
 * plugin level rather than by driving the picker thread itself.
 * ---------------------------------------------------------------------- */

/* Legacy path input: a job_elect_fn-only plugin, once registered and
 * resolved, comes back with job_elect_fn set AND picker_iface pointing at
 * plugin.c's legacy_picker_wrapper_iface (visible in this TU -- same
 * assertion test_plugin_picker_registration.c makes for plugin_register()
 * itself). This is exactly the condition
 * `if (job_picker->job_elect_fn != NULL) return
 * job_picker->job_elect_fn(job_picker);` in sched_job_picker() reads to
 * choose the "delegate to fcfs_elect_job-style forever loop" path. */
static void
test_resolved_legacy_plugin_has_job_elect_fn_set_selecting_legacy_branch(void)
{
    xce_scheduler_t     sched;
    xce_sched_plugin_t* legacy   = NULL;
    xce_sched_plugin_t* resolved = NULL;
    int                 rc;

    fixture_init(&sched);
    legacy = make_legacy_plugin("test_legacy_picker_for_wiring");
    TEST_ASSERT_GREATER_OR_EQUAL(0, plugin_register(&sched, legacy));

    sched.core.job_pick_plugin = "test_legacy_picker_for_wiring";

    rc = sched_resolve_job_picker(&sched.core, &resolved);

    TEST_ASSERT_EQUAL_INT(0, rc);
    TEST_ASSERT_NOT_NULL(resolved);
    TEST_ASSERT_NOT_NULL(resolved->job_elect_fn);
    TEST_ASSERT_EQUAL_PTR(&legacy_picker_wrapper_iface, resolved->picker_iface);
}

/* Native path input: builtin_fcfs, once registered and resolved, comes
 * back with job_elect_fn NULL -- the condition that selects the generic
 * picker_iface session loop instead. Distinct test from the "default"
 * test above: this one asserts on an EXPLICITLY configured name, not the
 * unset-defaults-to-builtin_fcfs path, isolating the branch condition
 * itself from the defaulting behavior. */
static void
test_resolved_builtin_fcfs_has_job_elect_fn_null_selecting_native_branch(void)
{
    xce_scheduler_t     sched;
    xce_sched_plugin_t* resolved = NULL;
    int                 rc;

    fixture_init(&sched);
    TEST_ASSERT_GREATER_OR_EQUAL(0, register_builtin_fcfs(&sched));

    sched.core.job_pick_plugin = "builtin_fcfs"; /* explicit, not defaulted */

    rc = sched_resolve_job_picker(&sched.core, &resolved);

    TEST_ASSERT_EQUAL_INT(0, rc);
    TEST_ASSERT_NOT_NULL(resolved);
    TEST_ASSERT_NULL(resolved->job_elect_fn);
    TEST_ASSERT_NOT_NULL(resolved->picker_iface);
    TEST_ASSERT_EQUAL_PTR(builtin_fcfs_next_job,
                          resolved->picker_iface->next_job);
}

/* Both builtin_fcfs and a legacy plugin can be registered simultaneously
 * (Req 3 AC 1's "wire builtin_fcfs as the registered default" does not
 * mean "the only" -- tasks.md's own builtin_fcfs.c header comment: fcfs.c
 * "stays registered ... reachable only by explicit config"). Confirms
 * choosing one by name does not disturb the other's own registration or
 * resolution. */
static void
test_legacy_and_native_pickers_coexist_and_resolve_independently(void)
{
    xce_scheduler_t     sched;
    xce_sched_plugin_t* legacy   = NULL;
    xce_sched_plugin_t* resolved = NULL;
    int                 rc;

    fixture_init(&sched);
    legacy = make_legacy_plugin("xce_sched_fcfs_stub");
    TEST_ASSERT_GREATER_OR_EQUAL(0, plugin_register(&sched, legacy));
    TEST_ASSERT_GREATER_OR_EQUAL(0, register_builtin_fcfs(&sched));

    sched.core.job_pick_plugin = "xce_sched_fcfs_stub";
    rc = sched_resolve_job_picker(&sched.core, &resolved);
    TEST_ASSERT_EQUAL_INT(0, rc);
    TEST_ASSERT_NOT_NULL(resolved->job_elect_fn);

    sched.core.job_pick_plugin = "builtin_fcfs";
    rc = sched_resolve_job_picker(&sched.core, &resolved);
    TEST_ASSERT_EQUAL_INT(0, rc);
    TEST_ASSERT_NULL(resolved->job_elect_fn);
}

int main(void)
{
    UNITY_BEGIN();
    RUN_TEST(test_register_builtin_fcfs_registers_under_name_builtin_fcfs);
    RUN_TEST(test_register_builtin_fcfs_is_native_not_legacy);
    RUN_TEST(test_register_builtin_fcfs_runs_init_via_init_fn_adapter);
    RUN_TEST(test_unset_job_pick_plugin_resolves_to_builtin_fcfs_by_default);
    RUN_TEST(
        test_unregistered_configured_name_fails_with_enoent_not_silent_fallback);
    RUN_TEST(test_registered_but_not_a_picker_fails_with_einval_not_enoent);
    RUN_TEST(test_unset_job_pick_plugin_without_defaulting_fails_with_einval);
    RUN_TEST(
        test_resolved_legacy_plugin_has_job_elect_fn_set_selecting_legacy_branch);
    RUN_TEST(
        test_resolved_builtin_fcfs_has_job_elect_fn_null_selecting_native_branch);
    RUN_TEST(test_legacy_and_native_pickers_coexist_and_resolve_independently);
    return UNITY_END();
}