refactor(coding-agent): reorganized test files to proper test directory structure

- Moved test files from src/core to test/core directory.
- Moved test files from src/core/tools to test/tools directory.
- Moved test files from src/discovery to test/discovery directory.
- Updated import paths to reflect new test file locations.

packages/coding-agent/test/tools/python-fallback.test.ts

@@ -0,0 +1,72 @@
+import { describe, expect, it, vi } from "bun:test";
+import * as pythonKernelModule from "../../src/core/python-kernel";
+import type { ToolSession } from "../../src/core/tools/index";
+import { createTools } from "../../src/core/tools/index";
+
+function createTestSession(overrides: Partial<ToolSession> = {}): ToolSession {
+	return {
+		cwd: "/tmp/test",
+		hasUI: false,
+		getSessionFile: () => null,
+		getSessionSpawns: () => "*",
+		...overrides,
+	};
+}
+
+function createBaseSettings(overrides: Partial<NonNullable<ToolSession["settings"]>> = {}) {
+	return {
+		getImageAutoResize: () => true,
+		getLspFormatOnWrite: () => true,
+		getLspDiagnosticsOnWrite: () => true,
+		getLspDiagnosticsOnEdit: () => false,
+		getEditFuzzyMatch: () => true,
+		getGitToolEnabled: () => true,
+		getBashInterceptorEnabled: () => true,
+		getBashInterceptorSimpleLsEnabled: () => true,
+		getBashInterceptorRules: () => [],
+		...overrides,
+	};
+}
+
+describe("createTools python fallback", () => {
+	it("falls back to bash-only when kernel unavailable", async () => {
+		const availabilitySpy = vi
+			.spyOn(pythonKernelModule, "checkPythonKernelAvailability")
+			.mockResolvedValue({ ok: false, reason: "unavailable" });
+
+		const session = createTestSession({
+			settings: createBaseSettings({
+				getPythonToolMode: () => "ipy-only",
+				getPythonKernelMode: () => "session",
+			}),
+		});
+
+		const tools = await createTools(session, ["python"]);
+		const names = tools.map((tool) => tool.name).sort();
+
+		expect(names).toEqual(["bash"]);
+
+		availabilitySpy.mockRestore();
+	});
+
+	it("keeps bash when python mode is both but unavailable", async () => {
+		const availabilitySpy = vi
+			.spyOn(pythonKernelModule, "checkPythonKernelAvailability")
+			.mockResolvedValue({ ok: false, reason: "unavailable" });
+
+		const session = createTestSession({
+			settings: createBaseSettings({
+				getPythonToolMode: () => "both",
+				getPythonKernelMode: () => "session",
+			}),
+		});
+
+		const tools = await createTools(session);
+		const names = tools.map((tool) => tool.name);
+
+		expect(names).toContain("bash");
+		expect(names).not.toContain("python");
+
+		availabilitySpy.mockRestore();
+	});
+});