vdm/daemon/tests/store_migrations_test.cpp

// The migrator: fresh DB -> head, idempotent re-run, and forward-only from every released
// user_version (M1 DoD: "a forward-only test from every released schema version").

#include <string>

#include "check.hpp"
#include "store/migrations.hpp"
#include "store/sqlite.hpp"

using namespace velox::daemon::store;

namespace {

std::int64_t head_version() {
    std::int64_t v = 0;
    for (const auto& m : embedded_migrations()) v = std::max(v, m.version);
    return v;
}

bool table_exists(Db& db, const char* name) {
    auto st = db.prepare("SELECT 1 FROM sqlite_master WHERE type='table' AND name=?1");
    if (!st) return false;
    if (!st->bind(1, std::string_view(name))) return false;
    auto row = st->step();
    return row && *row;
}

std::int64_t count(Db& db, const char* sql) {
    auto st = db.prepare(sql);
    if (!st) return -1;
    auto row = st->step();
    if (!row || !*row) return -1;
    return st->column_int(0);
}

}  // namespace

void run() {
    const std::int64_t head = head_version();
    CHECK(head >= 1);

    // --- fresh in-memory DB migrates cleanly to head --------------------------------
    {
        auto db = Db::open(":memory:");
        CHECK(db.has_value());
        if (!db) return;
        CHECK_EQ(db->user_version(), 0);

        auto out = migrate_to_head(*db);
        CHECK(out.has_value());
        if (out) {
            CHECK_EQ(out->from_version, 0);
            CHECK_EQ(out->to_version, head);
            CHECK_EQ(static_cast<std::int64_t>(out->applied), head);
        }
        CHECK_EQ(db->user_version(), head);

        for (const char* t : {"settings", "categories", "queues", "tasks", "segments",
                              "rules", "history", "pairings"}) {
            CHECK(table_exists(*db, t));
        }
        // Seed rows the initial migration inserts.
        CHECK_EQ(count(*db, "SELECT count(*) FROM categories WHERE builtin=1"), 6);
        CHECK_EQ(count(*db, "SELECT count(*) FROM queues"), 1);

        // FK + cascade wired: a segment for a missing task is rejected; deleting a task
        // takes its segments with it.
        CHECK(db->exec("INSERT INTO tasks(task_id,url,save_dir,created_at) "
                       "VALUES('t1','http://x','/tmp','2026-09-10T00:00:00Z')")
                  .has_value());
        CHECK(db->exec("INSERT INTO segments(task_id,idx,start_byte,end_byte) "
                       "VALUES('t1',0,0,99)")
                  .has_value());
        CHECK(!db->exec("INSERT INTO segments(task_id,idx,start_byte,end_byte) "
                        "VALUES('nope',0,0,99)")
                   .has_value());
        CHECK(db->exec("DELETE FROM tasks WHERE task_id='t1'").has_value());
        CHECK_EQ(count(*db, "SELECT count(*) FROM segments"), 0);

        // A whole-file zero-length download: one segment, end_byte = -1 (ADR 0010 B3a).
        CHECK(db->exec("INSERT INTO tasks(task_id,url,save_dir,created_at,size_bytes) "
                       "VALUES('z','http://x','/tmp','2026-09-10T00:00:00Z',0)")
                  .has_value());
        CHECK(db->exec("INSERT INTO segments(task_id,idx,start_byte,end_byte) "
                       "VALUES('z',0,0,-1)")
                  .has_value());
    }

    // --- re-running the migrator on an at-head DB is a no-op ------------------------
    {
        auto db = Db::open(":memory:");
        CHECK(db.has_value());
        (void)migrate_to_head(*db);
        auto again = migrate_to_head(*db);
        CHECK(again.has_value());
        if (again) {
            CHECK_EQ(again->applied, 0);
            CHECK_EQ(again->to_version, head);
        }
    }

    // --- forward-only: from every released version [0 .. head-1], reach head --------
    // A "released version N" db has the real schema migrations 1..N actually built, not
    // just the pragma set to N — faking the pragma alone left `start >= 1` cases running
    // a later migration (e.g. 0002's ALTER TABLE tasks / rebuild of segments) against a
    // db with no tables at all.
    for (std::int64_t start = 0; start < head; ++start) {
        auto db = Db::open(":memory:");
        CHECK(db.has_value());
        if (!db) continue;
        for (const auto& m : embedded_migrations()) {
            if (m.version > start) break;
            CHECK(db->exec(m.sql).has_value());
            CHECK(db->set_user_version(m.version).has_value());
        }
        CHECK_EQ(db->user_version(), start);
        auto out = migrate_to_head(*db);
        CHECK(out.has_value());
        if (out) {
            CHECK_EQ(out->from_version, start);
            CHECK_EQ(out->to_version, head);
        }
        CHECK_EQ(db->user_version(), head);
    }
}

TEST_MAIN()