repro: solder jumper bridge trace endpoint lands outside pad boundary (FP precision)

tests/solderjumper-fp-precision.test.ts

@@ -0,0 +1,42 @@
+import { test, expect } from "bun:test"
+import { convertCircuitJsonToPcbSvg } from "circuit-to-svg"
+import type { PcbSmtPad, PcbTrace } from "circuit-json"
+import { solderjumper } from "../src/fn/solderjumper"
+
+// These values (p=1.0414, pw=0.6604) are from the SparkFun Qwiic ToF Imager
+// VL53L5CX board. They are NOT exactly representable in IEEE 754 binary FP,
+// which triggers the compound error in the bridge trace endpoint calculation.
+test.failing(
+  "solderjumper bridge trace endpoint lands inside pad (FP precision)",
+  () => {
+    const result = solderjumper({
+      num_pins: 3,
+      bridged: "123",
+      p: 1.0414,
+      pw: 0.6604,
+      ph: 1.27,
+    })
+
+    const pads = result.circuitJson.filter(
+      (e): e is PcbSmtPad => e.type === "pcb_smtpad",
+    )
+    const traces = result.circuitJson.filter(
+      (e): e is PcbTrace => e.type === "pcb_trace",
+    )
+
+    const trace = traces[0]
+    const pad2 = pads.find((p) => p.port_hints?.includes("2"))!
+    const halfWidth = 0.6604 / 2
+
+    const svg = convertCircuitJsonToPcbSvg(result.circuitJson)
+    expect(svg).toMatchSvgSnapshot(
+      import.meta.path,
+      "solderjumper3_bridged123_p1.0414_pw0.6604_ph1.27",
+    )
+
+    // The endpoint at the pad edge should be within the pad boundary
+    // This fails because 1.0414 - 0.3302 = 0.7112 has a compound FP error
+    // making |0.7112 - 1.0414| = 0.33020000000000005 > 0.3302
+    expect(Math.abs(trace!.route[1].x - pad2!.x)).toBeLessThanOrEqual(halfWidth)
+  },
+)