diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 9d5381a..f67ed99 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -25,8 +25,8 @@ permissions:
 
 jobs:
   tests:
-    runs-on: ubuntu-latest
-    timeout-minutes: 30
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 60
     strategy:
       matrix:
         os:
@@ -68,15 +68,24 @@ jobs:
       - name: Generate test certificates
         run: bash tests/gen_certs.sh
 
+      # macOS runners have no Docker, so PostgreSQL is only available on Linux.
       - name: Start PostgreSQL
+        if: runner.os == 'Linux'
         run: docker compose up -d --wait
 
       - name: Install chronos
         run: nimble install chronos -y
 
+      # Linux runs the full suite against the live PostgreSQL above.
       - name: Run tests
+        if: runner.os == 'Linux'
         run: nimble test -y
 
+      # macOS has no PostgreSQL; run only the unit and mock-server tests.
+      - name: Run unit tests
+        if: runner.os != 'Linux'
+        run: nimble test_unit -y
+
       - name: Install async_postgres
         run: |
           rm -rf ~/.nimble/pkgs2/async_postgres-*
@@ -88,6 +97,8 @@ jobs:
       - name: Compile examples (chronos)
         run: for f in examples/*.nim; do nim c -d:asyncBackend=chronos "$f"; done
 
+      # Doc generation is platform-independent; run it once (on Linux).
       - name: Gen docs
+        if: runner.os == 'Linux'
         run: |
           nim doc --project --index:on --outdir:./htmldocs ./async_postgres.nim
diff --git a/async_postgres.nimble b/async_postgres.nimble
index bbdafad..fb32c31 100644
--- a/async_postgres.nimble
+++ b/async_postgres.nimble
@@ -11,6 +11,10 @@ requires "nim >= 2.2.4"
 requires "nimcrypto >= 0.6.0"
 requires "checksums >= 0.2.0"
 
-task test, "test":
+task test, "run the full suite (requires a live PostgreSQL on 127.0.0.1:15432)":
   exec "nim c -d:asyncBackend=asyncdispatch -r tests/all_tests.nim"
   exec "nim c -d:asyncBackend=chronos -r tests/all_tests.nim"
+
+task test_unit, "run unit and mock-server tests only (no PostgreSQL required)":
+  exec "nim c -d:asyncBackend=asyncdispatch -r tests/all_tests_unit.nim"
+  exec "nim c -d:asyncBackend=chronos -r tests/all_tests_unit.nim"
diff --git a/tests/all_tests.nim b/tests/all_tests.nim
index 2bff707..29d444e 100644
--- a/tests/all_tests.nim
+++ b/tests/all_tests.nim
@@ -1,8 +1,6 @@
+## Full test suite: the unit/mock tests plus the live-PostgreSQL integration
+## tests. Requires a running PostgreSQL (see docker-compose.yml). For a run
+## that needs no database, use all_tests_unit.nim instead.
 {.push warning[UnusedImport]: off.}
-import
-  test_abandonment_e2e, test_advisory_lock, test_auth, test_cancel_e2e, test_dsn,
-  test_e2e, test_fill_recvbuf, test_keepalive, test_largeobject, test_listen_reconnect,
-  test_network_failure, test_physical_replication, test_pool, test_protocol,
-  test_protocol_fuzz, test_replication, test_replication_keepalive, test_rowdata,
-  test_session_attrs, test_sql, test_ssl, test_tracing, test_types, test_pool_cluster
+import all_tests_unit, all_tests_integration
 {.pop.}
diff --git a/tests/all_tests_integration.nim b/tests/all_tests_integration.nim
new file mode 100644
index 0000000..736ef6c
--- /dev/null
+++ b/tests/all_tests_integration.nim
@@ -0,0 +1,8 @@
+## End-to-end tests that require a live PostgreSQL at 127.0.0.1:15432
+## (started via docker-compose.yml). Run these only where Docker/PostgreSQL
+## is available; the unit/mock suite lives in all_tests_unit.nim.
+{.push warning[UnusedImport]: off.}
+import
+  test_abandonment_e2e, test_advisory_lock, test_cancel_e2e, test_e2e, test_largeobject,
+  test_tracing
+{.pop.}
diff --git a/tests/all_tests_unit.nim b/tests/all_tests_unit.nim
new file mode 100644
index 0000000..1041209
--- /dev/null
+++ b/tests/all_tests_unit.nim
@@ -0,0 +1,11 @@
+## Unit and in-process mock-server tests. None of these require a live
+## PostgreSQL: every test either exercises pure logic or connects to an
+## in-process mock server on an ephemeral port. They therefore run anywhere,
+## including CI hosts without Docker (e.g. macOS runners).
+{.push warning[UnusedImport]: off.}
+import
+  test_auth, test_dsn, test_fill_recvbuf, test_keepalive, test_listen_reconnect,
+  test_network_failure, test_physical_replication, test_pool, test_pool_cluster,
+  test_protocol, test_protocol_fuzz, test_replication, test_replication_keepalive,
+  test_rowdata, test_session_attrs, test_sql, test_ssl, test_types
+{.pop.}
diff --git a/tests/test_keepalive.nim b/tests/test_keepalive.nim
index c91b57d..57bceb0 100644
--- a/tests/test_keepalive.nim
+++ b/tests/test_keepalive.nim
@@ -15,6 +15,11 @@ suite "configureKeepalive":
     doAssert fd != SocketHandle(-1), "socket() failed"
     fd
 
+  proc keepaliveEnabled(fd: SocketHandle): bool =
+    # macOS/BSD getsockopt returns the SO_KEEPALIVE flag bit (8), Linux returns 1,
+    # so treat any non-zero value as "enabled".
+    getIntSockOpt(fd, SOL_SOCKET, SO_KEEPALIVE) != 0
+
   test "keepAlive=false does not set SO_KEEPALIVE":
     let fd = makeSocket()
     defer:
@@ -22,7 +27,7 @@ suite "configureKeepalive":
     var config = ConnConfig()
     config.keepAlive = false
     configureKeepalive(fd, config)
-    check getIntSockOpt(fd, SOL_SOCKET, SO_KEEPALIVE) == 0
+    check not keepaliveEnabled(fd)
 
   test "keepAlive=true sets SO_KEEPALIVE":
     let fd = makeSocket()
@@ -31,7 +36,7 @@ suite "configureKeepalive":
     var config = ConnConfig()
     config.keepAlive = true
     configureKeepalive(fd, config)
-    check getIntSockOpt(fd, SOL_SOCKET, SO_KEEPALIVE) == 1
+    check keepaliveEnabled(fd)
 
   test "keepAlive with idle/interval/count":
     let fd = makeSocket()
@@ -43,7 +48,7 @@ suite "configureKeepalive":
     config.keepAliveInterval = 7
     config.keepAliveCount = 3
     configureKeepalive(fd, config)
-    check getIntSockOpt(fd, SOL_SOCKET, SO_KEEPALIVE) == 1
+    check keepaliveEnabled(fd)
     when defined(linux):
       check getIntSockOpt(fd, cint(posix.IPPROTO_TCP), TCP_KEEPIDLE) == 42
       check getIntSockOpt(fd, cint(posix.IPPROTO_TCP), TCP_KEEPINTVL) == 7
@@ -63,7 +68,7 @@ suite "configureKeepalive":
     config.keepAliveInterval = 0
     config.keepAliveCount = 0
     configureKeepalive(fd, config)
-    check getIntSockOpt(fd, SOL_SOCKET, SO_KEEPALIVE) == 1
+    check keepaliveEnabled(fd)
 
   test "keepAlive=false with timing params does not set SO_KEEPALIVE":
     let fd = makeSocket()
@@ -75,7 +80,7 @@ suite "configureKeepalive":
     config.keepAliveInterval = 10
     config.keepAliveCount = 3
     configureKeepalive(fd, config)
-    check getIntSockOpt(fd, SOL_SOCKET, SO_KEEPALIVE) == 0
+    check not keepaliveEnabled(fd)
 
   test "partial timing (idle only)":
     let fd = makeSocket()
@@ -85,7 +90,7 @@ suite "configureKeepalive":
     config.keepAlive = true
     config.keepAliveIdle = 99
     configureKeepalive(fd, config)
-    check getIntSockOpt(fd, SOL_SOCKET, SO_KEEPALIVE) == 1
+    check keepaliveEnabled(fd)
     when defined(linux):
       check getIntSockOpt(fd, cint(posix.IPPROTO_TCP), TCP_KEEPIDLE) == 99
     elif defined(macosx):