diff --git a/docs/howto/blueprints.rst b/docs/howto/blueprints.rst
index 3968c1006..0cbc1f0e8 100644
--- a/docs/howto/blueprints.rst
+++ b/docs/howto/blueprints.rst
@@ -5,16 +5,15 @@ Procrastinate provides Blueprints as a way to factor a large number of tasks
 into smaller self contained collections.
 
 You may want to create a collection for simple organsational reasons within the
-same project.  Or you may want to maintain a collection of tasks in a seperate
-package which is maintained independently of you Procrastinate server and
-workers. eg::
+same project. Or you may want to maintain a collection of tasks in a seperate
+package which is maintained independently of your Procrastinate codebase::
 
     ...
 
     from my_external_package import tasks_blueprint
     ...
 
-    app.register_blueprint(tasks_blueprint)
+    app.add_tasks_from(tasks_blueprint, namespace="my_external_package")
 
 
 Blueprints are easy to use, and task creation follows the pattern and API as
@@ -36,4 +35,4 @@ In your projcet register the blueprint with the `App` after you have created it:
 
     app = App(connector=AiopgConnector())
 
-    app.register_blueprint(my_blueprint)
+    app.add_tasks_from(my_blueprint, namespace="unique_name")
diff --git a/tests/acceptance/app.py b/tests/acceptance/app.py
index d0f8262f2..8a2e0121e 100644
--- a/tests/acceptance/app.py
+++ b/tests/acceptance/app.py
@@ -47,7 +47,8 @@ def sum_task(a, b):
     print(a + b)
 
 
-app.register_blueprint(bp)
+app.add_tasks_from(bp, namespace="ns")
+app.add_task_alias(sum_task, "tests.acceptance.app.sum_task")
 
 
 @app.task(queue="default")
diff --git a/tests/acceptance/test_nominal.py b/tests/acceptance/test_nominal.py
index d73780902..bd9dc5e2f 100644
--- a/tests/acceptance/test_nominal.py
+++ b/tests/acceptance/test_nominal.py
@@ -45,6 +45,7 @@ def test_nominal(defer, worker):
     defer("increment_task", a=3)
 
     stdout, stderr = worker()
+    print(stdout, stderr)
 
     assert stdout.splitlines() == ["Launching a worker on all queues", "12", "7", "4"]
     assert stderr.startswith("DEBUG:procrastinate.")
@@ -52,18 +53,22 @@ def test_nominal(defer, worker):
     defer("product_task", a=5, b=4)
 
     stdout, stderr = worker("default")
+    print(stdout, stderr)
     assert "20" not in stdout
 
     stdout, stderr = worker("product_queue")
+    print(stdout, stderr)
     assert stdout.splitlines() == ["Launching a worker on product_queue", "20"]
 
     defer("two_fails")
     stdout, stderr = worker()
+    print(stdout, stderr)
     assert "Print something to stdout" in stdout
     assert stderr.count("Exception: This should fail") == 2
 
     defer("multiple_exception_failures")
     stdout, stderr = worker()
+    print(stdout, stderr)
     assert (
         stdout
         == """Launching a worker on all queues
diff --git a/tests/acceptance/test_shell.py b/tests/acceptance/test_shell.py
index 2a3126695..96ededac4 100644
--- a/tests/acceptance/test_shell.py
+++ b/tests/acceptance/test_shell.py
@@ -16,48 +16,56 @@ def shell(process_env):
         yield proc
 
 
-def test_shell(shell, defer):
+@pytest.fixture
+def write(shell):
+    def _(s: str):
+        print(s, file=shell.stdin)
+
+    return _
+
+
+def test_shell(shell, write, defer):
     defer("sum_task", ["--lock=a"], a=5, b=7)
     defer("sum_task", ["--lock=lock"], a=3, b=8)
     defer("sum_task", ["--queue=other", "--lock=lock"], a=1, b=2)
     defer("increment_task", ["--lock=b"], a=5)
 
-    print("cancel 2", file=shell.stdin)
-    print("cancel 3", file=shell.stdin)
-    print("cancel 4", file=shell.stdin)
+    write("cancel 2")
+    write("cancel 3")
+    write("cancel 4")
 
-    print("list_jobs", file=shell.stdin)
-    print("list_jobs queue=other details", file=shell.stdin)
-    print("list_queues", file=shell.stdin)
-    print("list_tasks", file=shell.stdin)
-    print("list_locks", file=shell.stdin)
+    write("list_jobs")
+    write("list_jobs queue=other details")
+    write("list_queues")
+    write("list_tasks")
+    write("list_locks")
 
-    print("exit", file=shell.stdin)
+    write("exit")
     shell.stdin.close()
 
     assert shell.stdout.readlines() == [
         "Welcome to the procrastinate shell.   Type help or ? to list commands.\n",
         "\n",
         # cancel
-        "procrastinate> #2 tests.acceptance.app.sum_task on default - [failed]\n",
-        "procrastinate> #3 tests.acceptance.app.sum_task on other - [failed]\n",
+        "procrastinate> #2 ns:tests.acceptance.app.sum_task on default - [failed]\n",
+        "procrastinate> #3 ns:tests.acceptance.app.sum_task on other - [failed]\n",
         "procrastinate> #4 tests.acceptance.app.increment_task on default - [failed]\n",
         # list_jobs
-        "procrastinate> #1 tests.acceptance.app.sum_task on default - [todo]\n",
-        "#2 tests.acceptance.app.sum_task on default - [failed]\n",
-        "#3 tests.acceptance.app.sum_task on other - [failed]\n",
+        "procrastinate> #1 ns:tests.acceptance.app.sum_task on default - [todo]\n",
+        "#2 ns:tests.acceptance.app.sum_task on default - [failed]\n",
+        "#3 ns:tests.acceptance.app.sum_task on other - [failed]\n",
         "#4 tests.acceptance.app.increment_task on default - [failed]\n",
         # list_jobs queue=other details
-        "procrastinate> #3 tests.acceptance.app.sum_task on other - [failed] "
+        "procrastinate> #3 ns:tests.acceptance.app.sum_task on other - [failed] "
         "(attempts=0, scheduled_at=None, args={'a': 1, 'b': 2}, lock=lock)\n",
         # list_queues
         "procrastinate> default: 3 jobs (todo: 1, doing: 0, succeeded: 0, failed: 2)\n",
         "other: 1 jobs (todo: 0, doing: 0, succeeded: 0, failed: 1)\n",
         # list_tasks
+        "ns:tests.acceptance.app.sum_task: 3 jobs "
+        "(todo: 1, doing: 0, succeeded: 0, failed: 2)\n",
         "procrastinate> tests.acceptance.app.increment_task: 1 jobs "
         "(todo: 0, doing: 0, succeeded: 0, failed: 1)\n",
-        "tests.acceptance.app.sum_task: 3 jobs "
-        "(todo: 1, doing: 0, succeeded: 0, failed: 2)\n",
         "procrastinate> a: 1 jobs (todo: 1, doing: " "0, succeeded: 0, failed: 0)\n",
         "b: 1 jobs (todo: 0, doing: 0, succeeded: " "0, failed: 1)\n",
         "lock: 2 jobs (todo: 0, doing: 0, succeeded: 0, failed: 2)\n",
diff --git a/tests/conftest.py b/tests/conftest.py
index 801d349f2..af4e7a13a 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -16,7 +16,7 @@
 
 from procrastinate import aiopg_connector as aiopg_connector_module
 from procrastinate import app as app_module
-from procrastinate import jobs
+from procrastinate import builtin_tasks, jobs
 from procrastinate import psycopg2_connector as psycopg2_connector_module
 from procrastinate import schema, testing
 from procrastinate.contrib.sqlalchemy import (
@@ -168,7 +168,15 @@ def connector():
 
 
 @pytest.fixture
-def not_opened_app(connector):
+def reset_builtin_task_names():
+    builtin_tasks.remove_old_jobs.name = "procrastinate.builtin_tasks.remove_old_jobs"
+    builtin_tasks.builtin.tasks = {
+        task.name: task for task in builtin_tasks.builtin.tasks.values()
+    }
+
+
+@pytest.fixture
+def not_opened_app(connector, reset_builtin_task_names):
     return app_module.App(connector=connector)
 
 
diff --git a/tests/integration/test_worker.py b/tests/integration/test_worker.py
index ecdd39ae5..bd9ebed41 100644
--- a/tests/integration/test_worker.py
+++ b/tests/integration/test_worker.py
@@ -45,7 +45,6 @@ def t():
     # remove the periodic_deferrer_no_task log record because that makes the test flaky
     logs.pop("periodic_deferrer_no_task", None)
     assert list(logs.items()) == [
-        ("register_queue", "DEBUG"),
         ("about_to_defer_job", "DEBUG"),
         ("job_defer", "INFO"),
         ("loaded_job_info", "DEBUG"),
diff --git a/tests/unit/test_app.py b/tests/unit/test_app.py
index fe0def270..04487bbde 100644
--- a/tests/unit/test_app.py
+++ b/tests/unit/test_app.py
@@ -82,28 +82,15 @@ def wrapped():
 
 
 def test_app_register_builtins(app):
-    assert app.queues == {"builtin"}
     assert "procrastinate.builtin_tasks.remove_old_jobs" in app.tasks
-    assert "remove_old_jobs" in app.builtin_tasks
+    assert "builtin:procrastinate.builtin_tasks.remove_old_jobs" in app.tasks
 
 
 def test_app_register(app):
-    task = tasks.Task(task_func, app=app, queue="queue", name="bla")
+    task = tasks.Task(task_func, blueprint=app, queue="queue", name="bla")
 
-    app._register(task)
+    app._register_task(task)
 
-    assert app.queues == {"queue", "builtin"}
-    assert "bla" in app.tasks
-    assert app.tasks["bla"] == task
-
-
-def test_app_register_queue_already_exists(app):
-    app.queues.add("queue")
-    task = tasks.Task(task_func, app=app, queue="queue", name="bla")
-
-    app._register(task)
-
-    assert app.queues == {"queue", "builtin"}
     assert "bla" in app.tasks
     assert app.tasks["bla"] == task
 
diff --git a/tests/unit/test_blueprints.py b/tests/unit/test_blueprints.py
index fb87e0094..cbc0775d6 100644
--- a/tests/unit/test_blueprints.py
+++ b/tests/unit/test_blueprints.py
@@ -17,17 +17,17 @@ def test_app_task_explicit(app, mocker):
     def wrapped():
         return "foo"
 
-    app.register_blueprint(bp)
+    app.add_tasks_from(bp, namespace="ns")
 
     assert wrapped() == "foo"
-    assert app.tasks["foobar"].name == "foobar"
-    assert app.tasks["foobar"].queue == "bar"
-    assert app.tasks["foobar"].lock == "sher"
-    assert app.tasks["foobar"].queueing_lock == "baz"
-    assert isinstance(app.tasks["foobar"].retry_strategy, retry.RetryStrategy)
-    assert app.tasks["foobar"].pass_context is True
-    assert app.tasks["foobar"] is wrapped
-    assert app.tasks["foobar"].func is wrapped.__wrapped__
+    assert app.tasks["ns:foobar"].name == "ns:foobar"
+    assert app.tasks["ns:foobar"].queue == "bar"
+    assert app.tasks["ns:foobar"].lock == "sher"
+    assert app.tasks["ns:foobar"].queueing_lock == "baz"
+    assert isinstance(app.tasks["ns:foobar"].retry_strategy, retry.RetryStrategy)
+    assert app.tasks["ns:foobar"].pass_context is True
+    assert app.tasks["ns:foobar"] is wrapped
+    assert app.tasks["ns:foobar"].func is wrapped.__wrapped__
 
 
 def test_app_task_implicit(app):
@@ -37,12 +37,12 @@ def test_app_task_implicit(app):
     def wrapped():
         return "foo"
 
-    app.register_blueprint(bp)
+    app.add_tasks_from(bp, namespace="ns")
 
-    registered_task = app.tasks["tests.unit.test_blueprints.wrapped"]
+    registered_task = app.tasks["ns:tests.unit.test_blueprints.wrapped"]
 
     assert "foo" == wrapped()
-    assert "tests.unit.test_blueprints.wrapped" == registered_task.name
+    assert "ns:tests.unit.test_blueprints.wrapped" == registered_task.name
     assert "default" == registered_task.queue
     assert registered_task is wrapped
     assert registered_task.func is wrapped.__wrapped__
diff --git a/tests/unit/test_task_creation_signatures.py b/tests/unit/test_task_creation_signatures.py
deleted file mode 100644
index f2b2d6bb7..000000000
--- a/tests/unit/test_task_creation_signatures.py
+++ /dev/null
@@ -1,20 +0,0 @@
-import inspect
-
-from procrastinate import App, Blueprint
-from procrastinate.protocols import TaskCreator
-
-
-# def test_task_signatures(app, mocker):
-def test_task_signatures():
-    """Tasks can be created in two ways, both of which need to maintain an
-    identical API.  This test simple test that App.task and Blueprint.task have
-    the same function signature.
-
-    This is further enforced with protocols.TaskCreator and mypy checks.
-    """
-
-    # Check that both App.task and Blueprint.task implement Taskcreator.task
-    assert inspect.signature(App.task) == inspect.signature(TaskCreator.task)
-    assert inspect.signature(Blueprint.task) == inspect.signature(TaskCreator.task)
-    # Sanity check
-    assert inspect.signature(App.task) == inspect.signature(Blueprint.task)
diff --git a/tests/unit/test_tasks.py b/tests/unit/test_tasks.py
index e10ff816d..0a7f10047 100644
--- a/tests/unit/test_tasks.py
+++ b/tests/unit/test_tasks.py
@@ -10,7 +10,7 @@ def task_func():
 
 
 def test_task_init_with_no_name(app):
-    task = tasks.Task(task_func, app=app, queue="queue")
+    task = tasks.Task(task_func, blueprint=app, queue="queue")
 
     assert task.func is task_func
     assert task.name == "tests.unit.test_tasks.task_func"
@@ -18,7 +18,7 @@ def test_task_init_with_no_name(app):
 
 @pytest.mark.asyncio
 async def test_task_defer_async(app, connector):
-    task = tasks.Task(task_func, app=app, queue="queue")
+    task = tasks.Task(task_func, blueprint=app, queue="queue")
 
     await task.defer_async(c=3)
 
@@ -79,7 +79,7 @@ def test_configure_task_schedule_in_and_schedule_at(job_manager):
 
 
 def test_task_configure(app):
-    task = tasks.Task(task_func, app=app, queue="queue")
+    task = tasks.Task(task_func, blueprint=app, queue="queue")
 
     job = task.configure(lock="sher", task_kwargs={"yay": "ho"}).job
 
@@ -90,7 +90,7 @@ def test_task_configure(app):
 
 
 def test_task_configure_override_queue(app):
-    task = tasks.Task(task_func, app=app, queue="queue")
+    task = tasks.Task(task_func, blueprint=app, queue="queue")
 
     job = task.configure(queue="other_queue").job
 
@@ -98,7 +98,7 @@ def test_task_configure_override_queue(app):
 
 
 def test_task_get_retry_exception_none(app):
-    task = tasks.Task(task_func, app=app, queue="queue")
+    task = tasks.Task(task_func, blueprint=app, queue="queue")
     job = task.configure().job
 
     assert task.get_retry_exception(exception=None, job=job) is None
@@ -107,7 +107,7 @@ def test_task_get_retry_exception_none(app):
 def test_task_get_retry_exception(app, mocker):
     mock = mocker.patch("procrastinate.retry.RetryStrategy.get_retry_exception")
 
-    task = tasks.Task(task_func, app=app, queue="queue", retry=10)
+    task = tasks.Task(task_func, blueprint=app, queue="queue", retry=10)
     job = task.configure().job
 
     exception = ValueError()
diff --git a/tests/unit/test_worker.py b/tests/unit/test_worker.py
index 4b13c41af..bf3520ea7 100644
--- a/tests/unit/test_worker.py
+++ b/tests/unit/test_worker.py
@@ -193,7 +193,7 @@ def task_func(a, b):  # pylint: disable=unused-argument
         result.append(s)
         return s
 
-    task = tasks.Task(task_func, app=app, queue="yay", name="job")
+    task = tasks.Task(task_func, blueprint=app, queue="yay", name="job")
 
     app.tasks = {"task_func": task}
 
@@ -251,7 +251,7 @@ async def test_run_job_error(app):
     def job(a, b):  # pylint: disable=unused-argument
         raise ValueError("nope")
 
-    task = tasks.Task(job, app=app, queue="yay", name="job")
+    task = tasks.Task(job, blueprint=app, queue="yay", name="job")
     task.func = job
 
     app.tasks = {"job": task}
@@ -273,7 +273,7 @@ async def test_run_job_retry(app):
     def job(a, b):  # pylint: disable=unused-argument
         raise ValueError("nope")
 
-    task = tasks.Task(job, app=app, queue="yay", name="job", retry=True)
+    task = tasks.Task(job, blueprint=app, queue="yay", name="job", retry=True)
     task.func = job
 
     app.tasks = {"job": task}