diff --git a/package.nix b/package.nix
index b0fad51..08b6bbc 100644
--- a/package.nix
+++ b/package.nix
@@ -10,6 +10,7 @@
   rustHooks,
   rustPackages,
   versionCheckHook,
+  writeScript,
 }: lib.callWith' rustPackages ({
   rustPlatform,
   cargo,
@@ -37,12 +38,29 @@ in {
     cp -r --reflink=auto "$dynixCommand/"* "$out/"
     mkdir -p "$modules"
     cp -r --reflink=auto "$dynixModules/"* "$modules/"
+    install -Dm a=rx "$dynixTestingClient" "$out/libexec/dynix-testing-client.py"
   '';
 
   #
   # SUB-DERIVATONS
   #
 
+  dynixTestingClient = writeScript "dynix-testing-client.py" ''
+    #!/usr/bin/env python3
+    import socket, sys, os, json
+    try:
+        sockpath = sys.argv[1]
+    except IndexError:
+        sockpath = f"{os.environ['XDG_RUNTIME_DIR']}/dynix.sock"
+    sock = socket.socket(family=socket.AF_UNIX)
+    sock.connect(sockpath)
+    sock.sendall(sys.stdin.buffer.read())
+    sock.settimeout(20)
+    reply = json.loads(sock.recv(256).decode("utf-8"))
+    print(json.dumps(reply, indent=2))
+    sys.exit(reply["status"])
+  '';
+
   dynixCommand = stdenv.mkDerivation {
     pname = "${self.pname}-command";
     inherit (self) version;
diff --git a/src/daemon.rs b/src/daemon.rs
index 1a874ac..5f1b88c 100644
--- a/src/daemon.rs
+++ b/src/daemon.rs
@@ -195,6 +195,7 @@ impl Daemon {
         token
     }
 
+    #[expect(dead_code)]
     fn register_with_name<S>(&mut self, fd: RawFd, kind: FdKind, name: Box<OsStr>) -> Token {
         let token = next_token();
 
diff --git a/src/lib.rs b/src/lib.rs
index ab4d946..cfa921f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -231,6 +231,7 @@ pub fn get_next_prio_line(
     let penultimate = penultimate.unwrap();
 
     let new_generation = 0 - new_prio;
+    info!("setting '{option_name}' to '{new_value}' for generation '{new_generation}'");
 
     let new_line = SourceLine {
         line: penultimate.line,
diff --git a/tests/default.nix b/tests/default.nix
index 57b1c94..0541f6f 100644
--- a/tests/default.nix
+++ b/tests/default.nix
@@ -50,16 +50,11 @@
         requiredBy = [ "multi-user.target" ];
         after = [ "default.target" ];
         script = ''
-          if [[ -e /etc/nixos/hardware-configuration.nix ]]; then
-            echo "install-dynix: configuration already copied; nothing to do"
-            exit 0
-          fi
-
           nix profile install -vv "${dynix.drvPath}^*" # "
 
           mkdir -vp /etc/nixos
           nixos-generate-config
-          cp -rv --dereference /run/current-system/sw/share/nixos/*.nix /etc/nixos/
+          cp -rvf --dereference /run/current-system/sw/share/nixos/*.nix /etc/nixos/
           if ! [[ -e /etc/nixos/dynix-vm-configuration.nix ]]; then
             echo "FAILURE"
             echo "FAILURE" >&2
diff --git a/tests/dynix-vm-configuration.nix b/tests/dynix-vm-configuration.nix
index ee1c19b..677ef70 100644
--- a/tests/dynix-vm-configuration.nix
+++ b/tests/dynix-vm-configuration.nix
@@ -2,7 +2,7 @@
 #
 # SPDX-License-Identifier: EUPL-1.1
 
-{ pkgs, lib, modulesPath, ... }:
+{ pkgs, lib, modulesPath, config, ... }:
 let
   moduleList = import (modulesPath + "/module-list.nix");
 
@@ -64,9 +64,20 @@ in
     "NIXOS_CONFIG" = "/etc/nixos/configuration.nix";
   };
 
-  #systemd.services.dynix-daemon = {
-  #
-  #};
+  systemd.services.dynix-daemon = {
+    enable = true;
+    path = [ config.nix.package ];
+    serviceConfig = {
+      Environment = [
+        "RUST_LOG=trace"
+      ];
+      ExecSearchPath = [ "/run/current-system/sw/bin" ];
+      SuccessExitStatus = [ "0" "2" ];
+      # `bash -l` so XDG_RUNTIME_DIR is set correctly. lol.
+      ExecStart = "bash -l -c 'exec /root/.nix-profile/bin/dynix daemon --color=always'";
+      SyslogIdentifier = "dynix-daemon";
+    };
+  };
 
   environment.shellAliases = {
     ls = "eza --long --header --group --group-directories-first --classify --binary";
@@ -78,5 +89,6 @@ in
     ripgrep
     netcat.nc
     socat
+    python3
   ];
 }
diff --git a/tests/gotosocial/test-script.py b/tests/gotosocial/test-script.py
index eca3044..0f3131e 100644
--- a/tests/gotosocial/test-script.py
+++ b/tests/gotosocial/test-script.py
@@ -5,7 +5,7 @@
 from pathlib import Path
 import shlex
 import textwrap
-from typing import cast, TYPE_CHECKING
+from typing import Any, cast, TYPE_CHECKING
 
 from beartype import beartype
 
@@ -18,6 +18,13 @@ if TYPE_CHECKING:
     assert machine.shell is not None
 
 ls = "eza -lah --color=always --group-directories-first"
+testing_client = "/root/.nix-profile/libexec/dynix-testing-client.py"
+
+ANSI_RESET = "\x1b[0m"
+ANSI_BOLD = "\x1b[1m"
+ANSI_NOBOLD = "\x1b[22m"
+ANSI_RED = "\x1b[31m"
+ANSI_GREEN = "\x1b[32m"
 
 @beartype
 def run_log(machine: Machine, *commands: str, timeout: int | None = 60) -> str:
@@ -54,71 +61,108 @@ def get_config_file() -> str:
 
     config_file_path.unlink()
 
+    machine.logger.info(f"{ANSI_GREEN}INFO{ANSI_RESET}: got config file:")
+    machine.logger.info(textwrap.indent(data, "  "))
+
     return data
 
 @beartype
-def dynix_append(option: str, value: str):
+def dynix_append_cli(option: str, value: Any):
+    value = f'"{value}"' if isinstance(value, str) else value
     machine.succeed(f'''
         dynix append {shlex.quote(option)} {shlex.quote(value)}
     '''.strip())
 
-@beartype
-def do_apply():
     expr = textwrap.dedent("""
         (import <nixpkgs/nixos> { }).config.dynamicism.applyDynamicConfiguration { }
     """).strip()
-
-    machine.succeed(rf"""
+    machine.succeed(textwrap.dedent(rf"""
         nix run --show-trace --log-format raw-with-logs --impure -E {shlex.quote(expr)}
-    """.strip())
+    """).strip())
 
 
+@beartype
+def dynix_append_daemon(option: str, value: Any):
+    import json
+    payload = json.dumps(dict(
+        action="append",
+        args=dict(
+            name=option,
+            value=value,
+        ),
+    ))
+
+    machine.succeed(f"echo '{payload}' | {testing_client} /run/user/0/dynix.sock")
+
+@beartype
+def run_all_tests(machine: Machine, *, use_daemon: bool):
+    dynix_append = dynix_append_daemon if use_daemon else dynix_append_cli
+
+    dynix_out = machine.succeed("dynix --version")
+    assert "dynix" in dynix_out, f"dynix not in {dynix_out=}"
+
+    machine.succeed("systemctl start user@0.service")
+    machine.wait_for_unit("user@0.service")
+    machine.succeed("systemctl start dynix-daemon.service")
+    machine.wait_for_unit("dynix-daemon.service")
+
+    machine.log("REBUILDING configuration inside VM")
+    machine.succeed("env PAGER= nixos-rebuild switch --log-format raw-with-logs --no-reexec --fallback")
+    machine.wait_for_unit("gotosocial.service")
+
+    # Make sure the config before any dynamic changes is what we expect.
+    config_text = get_config_file()
+    lines = config_text.splitlines()
+    try:
+        application_name = next(line for line in lines if line.startswith("application-name:"))
+    except StopIteration:
+        raise AssertionError(f"no 'application-name:' found in config file: {textwrap.indent(config_text, "  ")}")
+    assert "gotosocial-for-machine" in application_name, f"'gotosocial-for-machine' should be in {application_name=}"
+
+    try:
+        host = next(line for line in lines if line.startswith("host:"))
+    except StopIteration:
+        raise AssertionError(f"no 'host:' found in config file: {textwrap.indent(config_text, "  ")}")
+    assert "gotosocial-machine" in host, f"'gotosocial-machine' should be in {host=}"
+
+    new_app_name = "yay!"
+    dynix_append("services.gotosocial.settings.application-name", f'{new_app_name}')
+
+    config_text = get_config_file()
+    lines = config_text.splitlines()
+    try:
+        application_name = next(line for line in lines if line.startswith("application-name:"))
+    except StopIteration:
+        raise AssertionError(f"no 'application-name:' found in config file: {textwrap.indent(config_text, "  ")}")
+    assert new_app_name in application_name, f"'{new_app_name}' should be in {application_name=}"
+
+    machine.log("REBUILDING configuration inside VM")
+    machine.succeed("env PAGER= nixos-rebuild switch --log-format raw-with-logs --no-reexec --fallback")
+
+    machine.wait_for_unit("gotosocial.service")
+
+    config_text = get_config_file()
+    lines = config_text.splitlines()
+    try:
+        application_name = next(line for line in lines if line.startswith("application-name:"))
+    except StopIteration:
+        raise AssertionError(f"no 'application-name:' found in config file: {textwrap.indent(config_text, "  ")}")
+    assert "gotosocial-for-machine" in application_name, f"'gotosocial-for-machine' should be in {application_name=}"
+
+machine.start(allow_reboot=True)
 machine.wait_for_unit("default.target")
 machine.wait_for_unit("install-dynix.service")
-
-dynix_out = machine.succeed("dynix --version")
-assert "dynix" in dynix_out, f"dynix not in {dynix_out=}"
-
-machine.log("REBUILDING configuration inside VM")
-machine.succeed("env PAGER= nixos-rebuild switch --log-format raw-with-logs --no-reexec --fallback")
-machine.wait_for_unit("gotosocial.service")
-
-# Make sure the config before any dynamic changes is what we expect.
-config_text = get_config_file()
-lines = config_text.splitlines()
 try:
-    application_name = next(line for line in lines if line.startswith("application-name:"))
-except StopIteration:
-    raise AssertionError(f"no 'application-name:' found in config file: {textwrap.indent(config_text, "  ")}")
-assert "gotosocial-for-machine" in application_name, f"'gotosocial-for-machine' should be in {application_name=}"
+    run_all_tests(machine, use_daemon=False)
+except Exception as e:
+    machine.logger.error(f"{ANSI_RED}ERROR{ANSI_RESET} during {ANSI_BOLD}CLI{ANSI_RESET} tests: {e}")
+    raise
 
+machine.reboot()
+
+machine.wait_for_unit("install-dynix.service")
 try:
-    host = next(line for line in lines if line.startswith("host:"))
-except StopIteration:
-    raise AssertionError(f"no 'host:' found in config file: {textwrap.indent(config_text, "  ")}")
-assert "gotosocial-machine" in host, f"'gotosocial-machine' should be in {host=}"
-
-new_app_name = "yay!"
-dynix_append("services.gotosocial.settings.application-name", f'"{new_app_name}"')
-do_apply()
-
-config_text = get_config_file()
-lines = config_text.splitlines()
-try:
-    application_name = next(line for line in lines if line.startswith("application-name:"))
-except StopIteration:
-    raise AssertionError(f"no 'application-name:' found in config file: {textwrap.indent(config_text, "  ")}")
-assert new_app_name in application_name, f"'{new_app_name}' should be in {application_name=}"
-
-machine.log("REBUILDING configuration inside VM")
-machine.succeed("env PAGER= nixos-rebuild switch --log-format raw-with-logs --no-reexec --fallback")
-
-machine.wait_for_unit("gotosocial.service")
-
-config_text = get_config_file()
-lines = config_text.splitlines()
-try:
-    application_name = next(line for line in lines if line.startswith("application-name:"))
-except StopIteration:
-    raise AssertionError(f"no 'application-name:' found in config file: {textwrap.indent(config_text, "  ")}")
-assert "gotosocial-for-machine" in application_name, f"'gotosocial-for-machine' should be in {application_name=}"
+    run_all_tests(machine, use_daemon=True)
+except Exception as e:
+    machine.logger.error(f"{ANSI_RED}ERROR{ANSI_RESET} during {ANSI_BOLD}daemon{ANSI_RESET} tests: {e}")
+    raise
diff --git a/tests/harmonia/test-script.py b/tests/harmonia/test-script.py
index e27b9ce..83ca0db 100644
--- a/tests/harmonia/test-script.py
+++ b/tests/harmonia/test-script.py
@@ -21,6 +21,7 @@ if TYPE_CHECKING:
     assert machine.shell is not None
 
 ls = "eza -lah --color=always --group-directories-first"
+testing_client = "/root/.nix-profile/libexec/dynix-testing-client.py"
 
 indent = functools.partial(textwrap.indent, prefix='  ')
 
@@ -65,9 +66,6 @@ def get_config_file() -> dict[str, Any]:
 
 @beartype
 def dynix_append_daemon(option: str, value: Any):
-    #machine.succeed(f'''
-    #    dynix append {shlex.quote(option)} {shlex.quote(str(value))}
-    #'''.strip())
     payload = json.dumps(dict(
         action="append",
         args=dict(
@@ -76,12 +74,10 @@ def dynix_append_daemon(option: str, value: Any):
         ),
     ))
 
-    machine.succeed(f'''
-        echo '{payload}' | socat -T10 -,ignoreeof /run/user/0/dynix.sock
-    ''')
+    machine.succeed(f"echo '{payload}' | {testing_client} /run/user/0/dynix.sock")
 
 @beartype
-def dynix_append_traditional(option: str, value: Any):
+def dynix_append_cli(option: str, value: Any):
     machine.succeed(f'''
         dynix append {shlex.quote(option)} {shlex.quote(str(value))}
     '''.strip())
@@ -94,76 +90,81 @@ def dynix_append_traditional(option: str, value: Any):
     """.strip())
 
 @beartype
-def dynix_append(option: str, value: Any):
-    use_daemon = True
-    #use_daemon = False
-    if use_daemon:
-        dynix_append_daemon(option, value)
-    else:
-        dynix_append_traditional(option, value)
+def run_all_tests(machine: Machine, *, use_daemon: bool):
+    dynix_append = dynix_append_daemon if use_daemon else dynix_append_cli
 
-machine.log("Doing test initialization and checks")
+    #
+    # Setup.
+    #
+    dynix_out = machine.succeed("dynix --version")
+    assert "dynix" in dynix_out, f"dynix not in {dynix_out=}"
 
-machine.wait_for_unit("default.target")
-machine.wait_for_unit("install-dynix.service")
+    machine.succeed("systemctl start user@0.service")
+    machine.wait_for_unit("user@0.service")
 
-dynix_out = machine.succeed("dynix --version")
-assert "dynix" in dynix_out, f"dynix not in {dynix_out=}"
+    run_log(machine, "systemctl start dynix-daemon.service")
+    machine.wait_for_unit("dynix-daemon.service")
 
-machine.succeed("systemctl start user@0.service")
-machine.wait_for_unit("user@0.service")
+    machine.log("Checking initial harmonia.service conditions")
 
-machine.succeed(textwrap.dedent(r'''
-    systemd-run --collect --unit=dynix-daemon.service \
-        -E "RUST_LOG=trace" \
-        -E "PATH=$PATH" \
-        -E "NIX_PATH=$NIX_PATH" \
-        -E "NIXOS_CONFIG=$NIXOS_CONFIG" \
-        -p "SuccessExitStatus=0 2" \
-        dynix daemon --color=always
-'''))
-machine.wait_for_unit("dynix-daemon.service")
+    # Config should have our initial values.
+    config_toml = get_config_file()
+    assert int(config_toml['workers']) == 4, f"{config_toml['workers']=} != 4"
+    assert int(config_toml['max_connection_rate']) == 256, f"{config_toml['max_connection_rate']=} != 256"
 
-machine.log("Checking initial harmonia.service conditions")
+    with machine.nested("must succeed: initial nixos-rebuild switch"):
+        machine.succeed("env PAGER= nixos-rebuild switch --log-format raw-with-logs --no-reexec -v --fallback")
 
-# Config should have our initial values.
-config_toml = get_config_file()
-assert int(config_toml['workers']) == 4, f"{config_toml['workers']=} != 4"
-assert int(config_toml['max_connection_rate']) == 256, f"{config_toml['max_connection_rate']=} != 256"
+    # Config should not have changed.
+    config_toml = get_config_file()
+    assert int(config_toml['workers']) == 4, f"{config_toml['workers']=} != 4"
+    assert int(config_toml['max_connection_rate']) == 256, f"{config_toml['max_connection_rate']=} != 256"
 
-with machine.nested("must succeed: initial nixos-rebuild switch"):
+    machine.log("Testing dynamic workers=20")
+    new_workers = 20
+    dynix_append("services.harmonia.settings.workers", new_workers)
+
+    machine.log("Testing that workers, but not max_connection_rate, changed")
+    # Workers, but not max connection rate, should have changed.
+    config_toml = get_config_file()
+    from pprint import pformat
+    machine.log(pformat(config_toml))
+    assert int(config_toml['workers']) == new_workers, f"{config_toml['workers']=} != {new_workers}"
+    assert int(config_toml['max_connection_rate']) == 256, f"{config_toml['max_connection_rate']=} != 256"
+
+    machine.log("Testing dynamic max_connection_rate=100")
+    new_max_connection_rate = 100
+    dynix_append("services.harmonia.settings.max_connection_rate", new_max_connection_rate)
+
+    # Max connection rate should have changed, and workers should be the same as before.
+    config_toml = get_config_file()
+    print(f"checking connection rate, {use_daemon=}")
+    assert int(config_toml['max_connection_rate']) == new_max_connection_rate, f"{config_toml['max_connection_rate']=} != {new_max_connection_rate}"
+    print(f"checking workers, {use_daemon=}")
+    assert int(config_toml['workers']) == new_workers, f"{config_toml['workers']=} != {new_workers}"
+
+    machine.log("Done with tests; stopping dynix-daemon")
+    machine.succeed("systemctl stop dynix-daemon.service")
+
+    # And this should set everything back.
     machine.succeed("env PAGER= nixos-rebuild switch --log-format raw-with-logs --no-reexec -v --fallback")
+    machine.wait_for_unit("harmonia.service")
+    config_toml = get_config_file()
+    assert int(config_toml['max_connection_rate']) == 256, f'{config_toml["max_connection_rate"]=} != 256'
+    assert int(config_toml['workers']) == 4, f'{config_toml["workers"]=} != 4'
 
-# Config should not have changed.
-config_toml = get_config_file()
-assert int(config_toml['workers']) == 4, f"{config_toml['workers']=} != 4"
-assert int(config_toml['max_connection_rate']) == 256, f"{config_toml['max_connection_rate']=} != 256"
+machine.start(allow_reboot=True)
+machine.wait_for_unit("install-dynix.service")
+try:
+    run_all_tests(machine, use_daemon=False)
+except Exception as e:
+    machine.log(f"ERROR running CLI tests: {e}")
 
-machine.log("Testing dynamic workers=20")
-new_workers = 20
-dynix_append("services.harmonia.settings.workers", new_workers)
+machine.reboot()
 
-machine.log("Testing that workers, but not max_connectin_rate, changed")
-# Workers, but not max connection rate, should have changed.
-config_toml = get_config_file()
-assert int(config_toml['workers']) == new_workers, f"{config_toml['workers']=} != {new_workers}"
-assert int(config_toml['max_connection_rate']) == 256, f"{config_toml['max_connection_rate']=} != 256"
-
-machine.log("Testing dynamic max_connection_rate=100")
-new_max_connection_rate = 100
-dynix_append("services.harmonia.settings.max_connection_rate", new_max_connection_rate)
-
-# Max connection rate should have changed, and workers should be the same as before.
-config_toml = get_config_file()
-assert int(config_toml['max_connection_rate']) == new_max_connection_rate, f"{config_toml['max_connection_rate']=} != {new_max_connection_rate}"
-assert int(config_toml['workers']) == new_workers, f"{config_toml['workers']=} != {new_workers}"
-
-machine.log("Done with tests; stopping dynix-daemon")
-machine.succeed("systemctl stop dynix-daemon.service")
-
-# And this should set everything back.
-machine.succeed("env PAGER= nixos-rebuild switch --log-format raw-with-logs --no-reexec -v --fallback")
-machine.wait_for_unit("harmonia.service")
-config_toml = get_config_file()
-assert int(config_toml['max_connection_rate']) == 256, f'{config_toml["max_connection_rate"]=} != 256'
-assert int(config_toml['workers']) == 4, f'{config_toml["workers"]=} != 4'
+machine.wait_for_unit("install-dynix.service")
+try:
+    run_all_tests(machine, use_daemon=True)
+except Exception as e:
+    machine.log(f"ERROR running DAEMON tests: {e}")
+    raise