feat: initial release

Assisted-by: GLM 5.3 Flash

integrate/fem2dnilmesh_test.go

@@ -0,0 +1,21 @@
+// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
+// SPDX-License-Identifier: MIT
+
+package integrate
+
+import "testing"
+
+// TestSolvePoissonFEM2DNilMeshRefused pins the nil-mesh refusal: the
+// three-dimensional solve reports a nil mesh as an error, so the
+// two-dimensional one answers the same way instead of dereferencing
+// it and panicking.
+func TestSolvePoissonFEM2DNilMeshRefused(t *testing.T) {
+	_, err := SolvePoissonFEM2D(nil, nil, FEMPoissonOptions{
+		Kappa:           1,
+		DirichletNodes:  []int{0},
+		DirichletValues: []float64{0},
+	})
+	if err == nil {
+		t.Fatal("SolvePoissonFEM2D: expected an error for a nil mesh")
+	}
+}