nx_gcode_arc_test.nx

nx_gcode_arc_test.nx -- verify arc-fit detection + G2/G3 emission. Test polygon: 4 vertices on a unit circle at 0°/90°/180°/270°: (1, 0), (0, 1), (-1, 0), (0, -1) [in Q14: 16384, 0, etc] All on circle centered at (0, 0) radius 1. Expected with arc_fit_enabled: - emitter walks polygon - prev_x=16384, prev_y=0 - tries arc through (16384,0), (0,16384), (-16384,0) - circle center (0,0) ok - extends with (0,-16384) -- on circle, fits - emits single G3 (or G2) from (16384,0) to (0,-16384) - closes loop back to (16384,0) with one G1 So output should contain "G3 X" (or "G2 X") string. With arc_fit_enabled=0 (default), output contains only "G1" moves (no "G2" or "G3"). Closed-form invariants: (a) Default disabled: emit produces NO G2/G3 (b) Setter enables -> setter returns 0 (c) Setter rejects out-of-range -> returns -1 (d) Enabled emit on circle-polygon -> output contains "G3 X" (e) Enabled emit on square (4 collinear-ish points NOT on circle) -> output still works; may or may not emit G3 (square IS a degenerate 4-pt-on-circle inscribed in a circle, so could arc-fit -- skip strict check for v1) expect_exit: 0 license_tier: ORIGINAL