fix gamepad layout and refuse a pad whose axes disagree

An Xbox One S pad over Bluetooth numbers its controls differently from the
indices this node shipped with: the right stick is on axes 2 and 3, the
triggers on 4 and 5, and the buttons carry gaps at 2 and 5. Against the old
layout an untouched pad reported a resting trigger as full right-stick
deflection, which asked for 30 deg/s of pitch while lying on the desk, held
the lease for ever so GAMEPAD_IDLE_RELEASE_S never fired, and moved a real
arm into a controller error. X toggled freedrive and LB was the E-STOP, so
the resulting latch could not be released from the pad at all.

Layout now carries the swept indices. Each pad is also measured the first
time it is seen at rest: a stick must rest near centre and a trigger near
the bottom of its travel, and a pad that does not fit reads as absent and is
named in the log rather than driving an arm from a numbering nobody checked.
The measured rest becomes each axis's zero, so a worn stick's tilt is
subtracted rather than deadzoned away and a trigger that reads 0 until it
first moves stops reading as half pressed.

Rest is never re-measured while the pad is in use, because doing that under
a held stick would record the deflection as centre and the arm would move
when the operator let go. The probe drives from the same calibration, so
what it prints is still what the arm would get, and it shows the mismatch.

Tests name their controls through axes_for and buttons_for instead of
numbering them; the positional lists are why a wrong index passed a green
suite.

tests/test_probe.py

@@ -2,7 +2,7 @@
 
 from dora_teleop import mapping, probe
 from dora_teleop.joy import Sample
-from tests.conftest import stick
+from tests.conftest import buttons_for, stick
 
 
 def test_a_centred_stick_puts_the_marker_in_the_middle():
@@ -28,7 +28,7 @@ def test_a_reading_beyond_full_deflection_stays_on_the_bar():
 def test_no_gamepad_says_so_and_says_the_arm_is_being_held_still(config):
     # Absence covers both "no pad" and "dora-joy stopped sending", and the probe
     # must not imply the arm is waiting on something it is not.
-    drawn = probe.render(Sample(present=False), [0.0] * 6, config)
+    drawn = probe.render(Sample(present=False), Sample(present=False), [0.0] * 6, config)
 
     assert "no gamepad" in drawn
     assert "hold still" in drawn
@@ -39,30 +39,31 @@ def test_every_axis_the_pad_reports_is_shown_even_the_unused_ones(config):
     # for, so nothing may be hidden.
     sample = Sample(axes=[0.0] * 8, buttons=[], present=True)
 
-    drawn = probe.render(sample, [0.0] * 6, config)
+    drawn = probe.render(sample, sample, [0.0] * 6, config)
 
     assert "unused" in drawn
     assert "axes (8 reported)" in drawn
 
 
 def test_a_pressed_button_is_named(config):
-    sample = stick(buttons=[True])
+    sample = stick(buttons=buttons_for(grasp=True))
 
-    drawn = probe.render(sample, [0.0] * 6, config)
+    drawn = probe.render(sample, sample, [0.0] * 6, config)
 
     assert "grasp" in drawn
 
 
 def test_nothing_pressed_says_so_rather_than_showing_an_empty_line(config):
-    drawn = probe.render(stick(), [0.0] * 6, config)
+    drawn = probe.render(stick(), stick(), [0.0] * 6, config)
 
     assert "none pressed" in drawn
 
 
 def test_the_velocity_is_shown_in_the_units_the_arm_takes(config):
-    velocity = mapping.velocity(stick(axes=[0.0, -1.0]).axes, [], config)
+    pushed = stick(axes=[0.0, -1.0])
+    velocity = mapping.velocity(pushed.axes, [], config)
 
-    drawn = probe.render(stick(axes=[0.0, -1.0]), velocity, config)
+    drawn = probe.render(pushed, pushed, velocity, config)
 
     assert "mm/s" in drawn
     assert "deg/s" in drawn
@@ -70,13 +71,14 @@ def test_the_velocity_is_shown_in_the_units_the_arm_takes(config):
 
 
 def test_a_still_arm_is_reported_as_still(config):
-    drawn = probe.render(stick(), [0.0] * 6, config)
+    drawn = probe.render(stick(), stick(), [0.0] * 6, config)
 
     assert "told to hold still" in drawn
 
 
 def test_a_moving_arm_is_reported_as_moving(config):
-    drawn = probe.render(stick(axes=[0.0, -1.0]), [10.0, 0, 0, 0, 0, 0], config)
+    pushed = stick(axes=[0.0, -1.0])
+    drawn = probe.render(pushed, pushed, [10.0, 0, 0, 0, 0, 0], config)
 
     assert "moving: yes" in drawn
 
@@ -84,5 +86,30 @@ def test_a_moving_arm_is_reported_as_moving(config):
 def test_whether_the_pad_is_asking_for_the_arm_is_shown(config):
     # The probe is where a resting trigger claiming the arm would have been
     # visible, so it says what `is_active` thinks rather than leaving it implied.
-    assert "asking for the arm: no" in probe.render(stick(), [0.0] * 6, config)
-    assert "asking for the arm: yes" in probe.render(stick(axes=[0.0, -1.0]), [0.0] * 6, config)
+    rest, pushed = stick(), stick(axes=[0.0, -1.0])
+
+    assert "asking for the arm: no" in probe.render(rest, rest, [0.0] * 6, config)
+    assert "asking for the arm: yes" in probe.render(pushed, pushed, [0.0] * 6, config)
+
+
+def test_a_pad_that_does_not_fit_the_layout_is_called_out(config):
+    # This is the tool for exactly that pad, so the reason goes on the screen
+    # rather than only in the node's log.
+    wrong = stick(axes=[0.0, 0.0, 0.0, -1.0, -1.0, -1.0])
+    mismatch = "axis 3 rests at -1.000, which is not where right stick Y sits"
+
+    drawn = probe.render(wrong, Sample(present=False), [0.0] * 6, config, mismatch)
+
+    assert "does not match the layout" in drawn
+    assert mismatch in drawn
+    assert "asking for the arm: no" in drawn
+
+
+def test_the_raw_axes_are_still_shown_for_a_pad_that_does_not_fit(config):
+    # The numbers are the evidence: they are what `Layout` gets corrected from.
+    wrong = stick(axes=[0.0, 0.0, 0.0, -1.0, -1.0, -1.0])
+
+    drawn = probe.render(wrong, Sample(present=False), [0.0] * 6, config, "axis 3")
+
+    assert "-1.000" in drawn
+    assert "axes (6 reported)" in drawn