diff --git a/tests/domain/spline-corridor-junctions.test.ts b/tests/domain/spline-corridor-junctions.test.ts
new file mode 100644
index 00000000..082ac8ef
--- /dev/null
+++ b/tests/domain/spline-corridor-junctions.test.ts
@@ -0,0 +1,176 @@
+import { describe, expect, it } from "vitest";
+
+import { createScenePath } from "../../src/document/paths";
+import { createSplineCorridorJunction } from "../../src/document/spline-corridor-junctions";
+import {
+  createSplineCorridorJunctionFromCandidate,
+  detectSplineCorridorJunctionCandidates,
+  resolveSplineCorridorJunctionClipIntervals
+} from "../../src/spline-corridor/spline-corridor-junctions";
+
+function createRoadPath(
+  id: string,
+  points: Array<{ x: number; y?: number; z: number }>
+) {
+  return createScenePath({
+    id,
+    road: {
+      enabled: true,
+      width: 2,
+      shoulderWidth: 1
+    },
+    points: points.map((point, index) => ({
+      id: `${id}-point-${index}`,
+      position: {
+        x: point.x,
+        y: point.y ?? 0,
+        z: point.z
+      }
+    }))
+  });
+}
+
+describe("spline corridor junctions", () => {
+  it("detects crossing road candidates without shared control points", () => {
+    const pathA = createRoadPath("path-a", [
+      { x: 0, z: 0 },
+      { x: 10, z: 0 }
+    ]);
+    const pathB = createRoadPath("path-b", [
+      { x: 5, z: -5 },
+      { x: 5, z: 5 }
+    ]);
+
+    const candidates = detectSplineCorridorJunctionCandidates({
+      paths: [pathA, pathB]
+    });
+
+    expect(candidates).toHaveLength(1);
+    expect(candidates[0]?.center).toMatchObject({ x: 5, y: 0, z: 0 });
+    expect(candidates[0]?.connections.map((connection) => connection.pathId)).toEqual([
+      "path-a",
+      "path-b"
+    ]);
+  });
+
+  it("detects self-intersections on non-adjacent spline segments", () => {
+    const path = createRoadPath("path-self", [
+      { x: 0, z: 0 },
+      { x: 10, z: 10 },
+      { x: 0, z: 10 },
+      { x: 10, z: 0 }
+    ]);
+
+    const candidates = detectSplineCorridorJunctionCandidates({
+      paths: [path]
+    });
+
+    expect(candidates).toHaveLength(1);
+    expect(candidates[0]?.connections).toEqual(
+      expect.arrayContaining([
+        expect.objectContaining({ pathId: "path-self" }),
+        expect.objectContaining({ pathId: "path-self" })
+      ])
+    );
+  });
+
+  it("rejects crossings with a large vertical gap", () => {
+    const lower = createRoadPath("path-lower", [
+      { x: 0, z: 0 },
+      { x: 10, z: 0 }
+    ]);
+    const upper = createRoadPath("path-upper", [
+      { x: 5, y: 4, z: -5 },
+      { x: 5, y: 4, z: 5 }
+    ]);
+
+    expect(
+      detectSplineCorridorJunctionCandidates({ paths: [lower, upper] })
+    ).toHaveLength(0);
+  });
+
+  it("detects near endpoint joins", () => {
+    const pathA = createRoadPath("path-end-a", [
+      { x: 0, z: 0 },
+      { x: 5, z: 0 }
+    ]);
+    const pathB = createRoadPath("path-end-b", [
+      { x: 5.2, z: 0 },
+      { x: 9, z: 0 }
+    ]);
+
+    const candidates = detectSplineCorridorJunctionCandidates({
+      paths: [pathA, pathB]
+    });
+
+    expect(candidates).toHaveLength(1);
+    expect(candidates[0]?.center.x).toBeCloseTo(5.1);
+  });
+
+  it("dedupes candidates covered by persisted junctions", () => {
+    const pathA = createRoadPath("path-existing-a", [
+      { x: 0, z: 0 },
+      { x: 10, z: 0 }
+    ]);
+    const pathB = createRoadPath("path-existing-b", [
+      { x: 5, z: -5 },
+      { x: 5, z: 5 }
+    ]);
+    const [candidate] = detectSplineCorridorJunctionCandidates({
+      paths: [pathA, pathB]
+    });
+
+    if (candidate === undefined) {
+      throw new Error("Expected candidate.");
+    }
+
+    const junction = createSplineCorridorJunctionFromCandidate(candidate);
+
+    expect(
+      detectSplineCorridorJunctionCandidates({
+        paths: [pathA, pathB],
+        junctions: {
+          [junction.id]: junction
+        }
+      })
+    ).toHaveLength(0);
+  });
+
+  it("resolves clip intervals from accepted junctions", () => {
+    const path = createRoadPath("path-clip", [
+      { x: 0, z: 0 },
+      { x: 10, z: 0 }
+    ]);
+    const junction = createSplineCorridorJunction({
+      id: "junction-clip",
+      center: { x: 5, y: 0, z: 0 },
+      radius: 1.5,
+      connections: [
+        {
+          pathId: path.id,
+          progress: 0.5,
+          clipDistance: 2
+        },
+        {
+          pathId: path.id,
+          progress: 0.8,
+          clipDistance: 1
+        }
+      ]
+    });
+
+    const intervals = resolveSplineCorridorJunctionClipIntervals({
+      paths: [path],
+      junctions: [junction]
+    }).get(path.id);
+
+    expect(intervals).toEqual([
+      expect.objectContaining({
+        junctionId: "junction-clip",
+        startDistance: 3,
+        endDistance: 9
+      })
+    ]);
+  });
+});
+