Removed the subdir.

pyrate/tests/act/test_lqr.py

@@ -0,0 +1,66 @@
+"""This module asserts correct runtime behaviour of the pyrate.act.pid module."""
+
+# Test environment
+from unittest import TestCase
+
+# Mathematics
+from numpy import array
+from numpy import eye
+from numpy import Inf
+from numpy.linalg import norm
+from numpy import vstack
+
+# Package under test
+from pyrate.act.control import Lqr
+
+
+class TestLqr(TestCase):
+
+    """Test for correct runtime behaviour in pyrate.act.control.lqr."""
+
+    # In this context, we reproduce a common controller notation
+    # pylint: disable=invalid-name
+
+    def setUp(self) -> None:
+        """Setup the LQR specification for testing."""
+
+        # Model specification
+        self.A = array([[0, 1], [0, 0]])
+        self.B = array([0, 1])[:, None]
+        self.C = array([1, 0])[None, :]
+        self.dt = 0.5
+
+        # Cost matrix specification
+        self.Q = eye(2)
+        self.R = array([[1.0]])
+
+        # State and target
+        # Target is already reached in this example
+        self.state = vstack([0.0, 0.0])
+        self.desired = vstack([0.0])
+
+    def test_process_tracking(self) -> None:
+        """Assert that a pandas.DataFrame with process data is created."""
+
+        # Initialize PID controller
+        lqr = Lqr(self.A, self.B, self.C, self.Q, self.R, self.dt, keep_trace=True)
+
+        # Execute a few control steps
+        state = self.state.copy()
+        previous_error = Inf
+        for _ in range(10):
+            control_signal = lqr.control(desired=self.desired, state=self.state)
+            state += self.A.dot(state) + self.B.dot(control_signal)
+            error = norm(state - self.desired).item()  # Convert from numpy scalar to Python float
+            assert error < previous_error or error == 0, "Error did not get lower."
+            previous_error = error
+
+        # Assert correct process tracing with LQR controller
+        assert lqr.process is not None, "LQR did not keep trace of process"
+        assert len(lqr.process.index) == 10, "LQR has not traced enough steps"
+
+        # Reset PID
+        lqr.reset()
+
+        # Assert correct reset to initial state
+        assert len(lqr.process.index) == 0, "LQR has not dropped process trace properly"