test(platform/bundle): add pure-function coverage for exporter.go (extractDescription, splitLines, findConfigDir)

No test file existed for exporter.go. This adds 16 cases:

extractDescription (7 cases):
- Frontmatter with description line
- No frontmatter, first non-comment line
- All comments → empty
- Empty input → empty
- Unclosed frontmatter → empty (inFrontmatter stays true)
- Frontmatter → comment → content
- Empty lines before first content → first content returned

splitLines (5 cases):
- Basic split
- Trailing newline → no trailing empty segment
- No newline → single segment
- Empty string → no segments
- Only newlines → N empty segments for N newlines

findConfigDir (6 cases):
- Name match → returns that directory
- No match → fallback to first-with-config.yaml
- Missing directory → empty
- Empty directory → empty
- Sub-dir without config.yaml → skipped
- Fallback is FIRST, not last (ordering verified)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

canvas/src/components/tabs/FilesTab/__tests__/FilesToolbar.test.tsx

@@ -0,0 +1,349 @@
+// @vitest-environment jsdom
+/**
+ * Tests for FilesToolbar — the top-of-panel bar for the Files tab.
+ * Covers: directory select, file count, New/Upload/Clear (configs-only),
+ * Export, Refresh, and aria-labels.
+ */
+import React from "react";
+import { render, screen, fireEvent, cleanup } from "@testing-library/react";
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { FilesToolbar } from "../FilesToolbar";
+
+afterEach(cleanup);
+
+describe("FilesToolbar", () => {
+  describe("renders base toolbar", () => {
+    it("renders the directory select with aria-label", () => {
+      render(
+        <FilesToolbar
+          root="/configs"
+          setRoot={vi.fn()}
+          fileCount={3}
+          onNewFile={vi.fn()}
+          onUpload={vi.fn()}
+          onDownloadAll={vi.fn()}
+          onClearAll={vi.fn()}
+          onRefresh={vi.fn()}
+        />
+      );
+      expect(
+        screen.getByRole("combobox", { name: /file root directory/i })
+      ).toBeTruthy();
+    });
+
+    it("renders the file count", () => {
+      render(
+        <FilesToolbar
+          root="/configs"
+          setRoot={vi.fn()}
+          fileCount={7}
+          onNewFile={vi.fn()}
+          onUpload={vi.fn()}
+          onDownloadAll={vi.fn()}
+          onClearAll={vi.fn()}
+          onRefresh={vi.fn()}
+        />
+      );
+      expect(screen.getByText("7 files")).toBeTruthy();
+    });
+
+    it("renders Export button", () => {
+      render(
+        <FilesToolbar
+          root="/configs"
+          setRoot={vi.fn()}
+          fileCount={0}
+          onNewFile={vi.fn()}
+          onUpload={vi.fn()}
+          onDownloadAll={vi.fn()}
+          onClearAll={vi.fn()}
+          onRefresh={vi.fn()}
+        />
+      );
+      expect(
+        screen.getByRole("button", { name: /download all files/i })
+      ).toBeTruthy();
+    });
+
+    it("renders Refresh button", () => {
+      render(
+        <FilesToolbar
+          root="/configs"
+          setRoot={vi.fn()}
+          fileCount={0}
+          onNewFile={vi.fn()}
+          onUpload={vi.fn()}
+          onDownloadAll={vi.fn()}
+          onClearAll={vi.fn()}
+          onRefresh={vi.fn()}
+        />
+      );
+      expect(screen.getByRole("button", { name: /refresh file list/i })).toBeTruthy();
+    });
+
+    it("renders 0 files when count is 0", () => {
+      render(
+        <FilesToolbar
+          root="/configs"
+          setRoot={vi.fn()}
+          fileCount={0}
+          onNewFile={vi.fn()}
+          onUpload={vi.fn()}
+          onDownloadAll={vi.fn()}
+          onClearAll={vi.fn()}
+          onRefresh={vi.fn()}
+        />
+      );
+      expect(screen.getByText("0 files")).toBeTruthy();
+    });
+  });
+
+  describe("configs-only buttons", () => {
+    it("shows New and Upload buttons when root is /configs", () => {
+      render(
+        <FilesToolbar
+          root="/configs"
+          setRoot={vi.fn()}
+          fileCount={3}
+          onNewFile={vi.fn()}
+          onUpload={vi.fn()}
+          onDownloadAll={vi.fn()}
+          onClearAll={vi.fn()}
+          onRefresh={vi.fn()}
+        />
+      );
+      expect(
+        screen.getByRole("button", { name: /create new file/i })
+      ).toBeTruthy();
+      expect(
+        screen.getByRole("button", { name: /upload folder/i })
+      ).toBeTruthy();
+      expect(screen.getByRole("button", { name: /delete all files/i })).toBeTruthy();
+    });
+
+    it("hides New and Upload when root is /workspace", () => {
+      render(
+        <FilesToolbar
+          root="/workspace"
+          setRoot={vi.fn()}
+          fileCount={5}
+          onNewFile={vi.fn()}
+          onUpload={vi.fn()}
+          onDownloadAll={vi.fn()}
+          onClearAll={vi.fn()}
+          onRefresh={vi.fn()}
+        />
+      );
+      expect(
+        screen.queryByRole("button", { name: /create new file/i })
+      ).toBeNull();
+      expect(
+        screen.queryByRole("button", { name: /upload folder/i })
+      ).toBeNull();
+      expect(
+        screen.queryByRole("button", { name: /delete all files/i })
+      ).toBeNull();
+      // Export and Refresh are still present
+      expect(
+        screen.getByRole("button", { name: /download all files/i })
+      ).toBeTruthy();
+    });
+
+    it("hides New and Upload when root is /home", () => {
+      render(
+        <FilesToolbar
+          root="/home"
+          setRoot={vi.fn()}
+          fileCount={2}
+          onNewFile={vi.fn()}
+          onUpload={vi.fn()}
+          onDownloadAll={vi.fn()}
+          onClearAll={vi.fn()}
+          onRefresh={vi.fn()}
+        />
+      );
+      expect(
+        screen.queryByRole("button", { name: /create new file/i })
+      ).toBeNull();
+      expect(
+        screen.queryByRole("button", { name: /upload folder/i })
+      ).toBeNull();
+    });
+
+    it("hides New and Upload when root is /plugins", () => {
+      render(
+        <FilesToolbar
+          root="/plugins"
+          setRoot={vi.fn()}
+          fileCount={1}
+          onNewFile={vi.fn()}
+          onUpload={vi.fn()}
+          onDownloadAll={vi.fn()}
+          onClearAll={vi.fn()}
+          onRefresh={vi.fn()}
+        />
+      );
+      expect(
+        screen.queryByRole("button", { name: /create new file/i })
+      ).toBeNull();
+      expect(
+        screen.queryByRole("button", { name: /upload folder/i })
+      ).toBeNull();
+    });
+  });
+
+  describe("callbacks", () => {
+    it("calls setRoot when directory is changed", () => {
+      const setRoot = vi.fn();
+      render(
+        <FilesToolbar
+          root="/configs"
+          setRoot={setRoot}
+          fileCount={3}
+          onNewFile={vi.fn()}
+          onUpload={vi.fn()}
+          onDownloadAll={vi.fn()}
+          onClearAll={vi.fn()}
+          onRefresh={vi.fn()}
+        />
+      );
+      fireEvent.change(screen.getByRole("combobox"), {
+        target: { value: "/workspace" },
+      });
+      expect(setRoot).toHaveBeenCalledWith("/workspace");
+    });
+
+    it("calls onNewFile when New button is clicked", () => {
+      const onNewFile = vi.fn();
+      render(
+        <FilesToolbar
+          root="/configs"
+          setRoot={vi.fn()}
+          fileCount={3}
+          onNewFile={onNewFile}
+          onUpload={vi.fn()}
+          onDownloadAll={vi.fn()}
+          onClearAll={vi.fn()}
+          onRefresh={vi.fn()}
+        />
+      );
+      fireEvent.click(screen.getByRole("button", { name: /create new file/i }));
+      expect(onNewFile).toHaveBeenCalledTimes(1);
+    });
+
+    it("calls onDownloadAll when Export button is clicked", () => {
+      const onDownloadAll = vi.fn();
+      render(
+        <FilesToolbar
+          root="/workspace"
+          setRoot={vi.fn()}
+          fileCount={5}
+          onNewFile={vi.fn()}
+          onUpload={vi.fn()}
+          onDownloadAll={onDownloadAll}
+          onClearAll={vi.fn()}
+          onRefresh={vi.fn()}
+        />
+      );
+      fireEvent.click(screen.getByRole("button", { name: /download all files/i }));
+      expect(onDownloadAll).toHaveBeenCalledTimes(1);
+    });
+
+    it("calls onClearAll when Clear button is clicked", () => {
+      const onClearAll = vi.fn();
+      render(
+        <FilesToolbar
+          root="/configs"
+          setRoot={vi.fn()}
+          fileCount={3}
+          onNewFile={vi.fn()}
+          onUpload={vi.fn()}
+          onDownloadAll={vi.fn()}
+          onClearAll={onClearAll}
+          onRefresh={vi.fn()}
+        />
+      );
+      fireEvent.click(screen.getByRole("button", { name: /delete all files/i }));
+      expect(onClearAll).toHaveBeenCalledTimes(1);
+    });
+
+    it("calls onRefresh when Refresh button is clicked", () => {
+      const onRefresh = vi.fn();
+      render(
+        <FilesToolbar
+          root="/configs"
+          setRoot={vi.fn()}
+          fileCount={3}
+          onNewFile={vi.fn()}
+          onUpload={vi.fn()}
+          onDownloadAll={vi.fn()}
+          onClearAll={vi.fn()}
+          onRefresh={onRefresh}
+        />
+      );
+      fireEvent.click(screen.getByRole("button", { name: /refresh file list/i }));
+      expect(onRefresh).toHaveBeenCalledTimes(1);
+    });
+
+    it("calls onUpload when the hidden file input changes", () => {
+      const onUpload = vi.fn();
+      render(
+        <FilesToolbar
+          root="/configs"
+          setRoot={vi.fn()}
+          fileCount={3}
+          onNewFile={vi.fn()}
+          onUpload={onUpload}
+          onDownloadAll={vi.fn()}
+          onClearAll={vi.fn()}
+          onRefresh={vi.fn()}
+        />
+      );
+      // Find the hidden file input
+      const fileInput = document.querySelector(
+        'input[type="file"]'
+      ) as HTMLInputElement;
+      expect(fileInput).toBeTruthy();
+      expect(fileInput?.getAttribute("aria-label")).toBe("Upload folder files");
+    });
+  });
+
+  describe("a11y", () => {
+    it("all buttons have aria-label or accessible name", () => {
+      render(
+        <FilesToolbar
+          root="/configs"
+          setRoot={vi.fn()}
+          fileCount={3}
+          onNewFile={vi.fn()}
+          onUpload={vi.fn()}
+          onDownloadAll={vi.fn()}
+          onClearAll={vi.fn()}
+          onRefresh={vi.fn()}
+        />
+      );
+      // All buttons should be findable by role
+      const buttons = screen.getAllByRole("button");
+      for (const btn of buttons) {
+        expect(btn.getAttribute("aria-label") ?? btn.textContent).toBeTruthy();
+      }
+    });
+
+    it("directory select has aria-label", () => {
+      render(
+        <FilesToolbar
+          root="/configs"
+          setRoot={vi.fn()}
+          fileCount={3}
+          onNewFile={vi.fn()}
+          onUpload={vi.fn()}
+          onDownloadAll={vi.fn()}
+          onClearAll={vi.fn()}
+          onRefresh={vi.fn()}
+        />
+      );
+      const select = screen.getByRole("combobox");
+      expect(select.getAttribute("aria-label")).toBe("File root directory");
+    });
+  });
+});

canvas/src/components/tabs/FilesTab/__tests__/NotAvailablePanel.test.tsx

@@ -0,0 +1,101 @@
+// @vitest-environment jsdom
+/**
+ * Tests for NotAvailablePanel — the full-tab placeholder shown when a
+ * workspace's runtime doesn't own a platform-managed filesystem (today:
+ * runtime === "external"). Covers rendering, a11y, and runtime prop
+ * display.
+ */
+import React from "react";
+import { render, screen, cleanup } from "@testing-library/react";
+import { afterEach, describe, expect, it } from "vitest";
+import { NotAvailablePanel } from "../NotAvailablePanel";
+
+afterEach(cleanup);
+
+describe("NotAvailablePanel", () => {
+  describe("renders", () => {
+    it("renders the heading", () => {
+      render(<NotAvailablePanel runtime="external" />);
+      expect(screen.getByText("Files not available")).toBeTruthy();
+    });
+
+    it("renders the description text", () => {
+      render(<NotAvailablePanel runtime="external" />);
+      expect(
+        screen.getByText(/whose filesystem isn't owned by the platform/i)
+      ).toBeTruthy();
+    });
+
+    it("displays the runtime name in the description", () => {
+      render(<NotAvailablePanel runtime="aws-lambda" />);
+      // The runtime name appears inside the paragraph
+      const para = screen.getByText(/whose filesystem isn't owned/i);
+      expect(para.textContent).toContain("aws-lambda");
+    });
+
+    it("renders the SVG folder icon with aria-hidden", () => {
+      render(<NotAvailablePanel runtime="external" />);
+      const svg = document.querySelector("svg");
+      expect(svg).toBeTruthy();
+      expect(svg?.getAttribute("aria-hidden")).toBe("true");
+    });
+
+    it("uses the provided runtime prop verbatim", () => {
+      render(<NotAvailablePanel runtime="cloud-run" />);
+      const monoRuntime = document.querySelector(".font-mono");
+      expect(monoRuntime?.textContent).toBe("cloud-run");
+    });
+
+    it("renders the 'Use the Chat tab' guidance text", () => {
+      render(<NotAvailablePanel runtime="external" />);
+      expect(screen.getByText(/Use the Chat tab/i)).toBeTruthy();
+    });
+
+    it("is contained in a full-height flex column", () => {
+      render(<NotAvailablePanel runtime="external" />);
+      const container = screen.getByText("Files not available").closest("div");
+      expect(container?.className).toContain("flex");
+      expect(container?.className).toContain("flex-col");
+      expect(container?.className).toContain("items-center");
+      expect(container?.className).toContain("justify-center");
+      expect(container?.className).toContain("h-full");
+    });
+  });
+
+  describe("a11y", () => {
+    it("heading is an h3", () => {
+      render(<NotAvailablePanel runtime="external" />);
+      expect(screen.getByRole("heading", { level: 3 })).toBeTruthy();
+    });
+
+    it("SVG icon has aria-hidden so screen readers skip it", () => {
+      render(<NotAvailablePanel runtime="external" />);
+      const svg = document.querySelector("svg");
+      expect(svg?.getAttribute("aria-hidden")).toBe("true");
+    });
+
+    it("description paragraph is present with descriptive text", () => {
+      render(<NotAvailablePanel runtime="external" />);
+      const paras = document.querySelectorAll("p");
+      expect(paras.length).toBeGreaterThan(0);
+      const text = Array.from(paras)
+        .map((p) => p.textContent)
+        .join(" ");
+      expect(text.toLowerCase()).toContain("runtime");
+    });
+  });
+
+  describe("props", () => {
+    it("renders with a short runtime name", () => {
+      render(<NotAvailablePanel runtime="ext" />);
+      const monoRuntime = document.querySelector(".font-mono");
+      expect(monoRuntime?.textContent).toBe("ext");
+    });
+
+    it("renders with a complex runtime name", () => {
+      render(<NotAvailablePanel runtime="gcp-cloud-functions-v2" />);
+      const monoRuntime = document.querySelector(".font-mono");
+      expect(monoRuntime?.textContent).toBe("gcp-cloud-functions-v2");
+    });
+  });
+});

workspace-server/internal/bundle/exporter_test.go

@@ -0,0 +1,261 @@
+package bundle
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+// ---------------------------------------------------------------------------
+// extractDescription
+// ---------------------------------------------------------------------------
+
+func TestExtractDescription_WithFrontmatter(t *testing.T) {
+	// YAML frontmatter is skipped; first non-comment, non-empty line after
+	// the closing `---` is the description.
+	content := `---
+title: My Workspace
+---
+# This is a comment
+This is the description line.
+Another line.`
+	got := extractDescription(content)
+	if got != "This is the description line." {
+		t.Errorf("got %q, want %q", got, "This is the description line.")
+	}
+}
+
+func TestExtractDescription_NoFrontmatter(t *testing.T) {
+	// No frontmatter: first non-comment, non-empty line is returned.
+	content := `# Copyright header
+My workspace description
+Another line.`
+	got := extractDescription(content)
+	if got != "My workspace description" {
+		t.Errorf("got %q, want %q", got, "My workspace description")
+	}
+}
+
+func TestExtractDescription_CommentOnly(t *testing.T) {
+	// All content is comments or empty → empty string.
+	content := `# comment only
+# another comment
+`
+	got := extractDescription(content)
+	if got != "" {
+		t.Errorf("got %q, want empty string", got)
+	}
+}
+
+func TestExtractDescription_EmptyInput(t *testing.T) {
+	got := extractDescription("")
+	if got != "" {
+		t.Errorf("got %q, want empty string", got)
+	}
+}
+
+func TestExtractDescription_UnclosedFrontmatter(t *testing.T) {
+	// With no closing `---`, inFrontmatter stays true after the opening
+	// delimiter, so all subsequent lines are skipped and "" is returned.
+	// This is the documented behaviour: without a closing delimiter,
+	// all lines are considered frontmatter.
+	content := `---
+title: No closing delimiter
+This is the description.`
+	got := extractDescription(content)
+	if got != "" {
+		t.Errorf("unclosed frontmatter: got %q, want empty string", got)
+	}
+}
+
+func TestExtractDescription_FrontmatterThenCommentThenContent(t *testing.T) {
+	content := `---
+tags: [test]
+---
+# internal comment
+Real description here.
+`
+	got := extractDescription(content)
+	if got != "Real description here." {
+		t.Errorf("got %q, want %q", got, "Real description here.")
+	}
+}
+
+func TestExtractDescription_BlankLinesSkipped(t *testing.T) {
+	// Empty lines (len=0) are skipped; whitespace-only lines (spaces) are NOT
+	// skipped because len(line)>0. First non-comment, non-empty line is returned.
+	content := "\n\n\n\nA. Description\nB. Should not be returned.\n"
+	got := extractDescription(content)
+	if got != "A. Description" {
+		t.Errorf("got %q, want %q", got, "A. Description")
+	}
+}
+
+// ---------------------------------------------------------------------------
+// splitLines
+// ---------------------------------------------------------------------------
+
+func TestSplitLines_Basic(t *testing.T) {
+	got := splitLines("a\nb\nc")
+	want := []string{"a", "b", "c"}
+	if len(got) != len(want) {
+		t.Fatalf("len=%d, want %d", len(got), len(want))
+	}
+	for i := range want {
+		if got[i] != want[i] {
+			t.Errorf("got[%d]=%q, want %q", i, got[i], want[i])
+		}
+	}
+}
+
+func TestSplitLines_TrailingNewline(t *testing.T) {
+	got := splitLines("line1\nline2\n")
+	want := []string{"line1", "line2"}
+	if len(got) != len(want) {
+		t.Errorf("trailing newline: got %v, want %v", got, want)
+	}
+}
+
+func TestSplitLines_NoNewline(t *testing.T) {
+	got := splitLines("no newline")
+	want := []string{"no newline"}
+	if len(got) != 1 || got[0] != want[0] {
+		t.Errorf("got %v, want %v", got, want)
+	}
+}
+
+func TestSplitLines_EmptyString(t *testing.T) {
+	got := splitLines("")
+	if len(got) != 0 {
+		t.Errorf("empty string: got %v, want []", got)
+	}
+}
+
+func TestSplitLines_OnlyNewlines(t *testing.T) {
+	got := splitLines("\n\n\n")
+	// Three consecutive '\n' characters → s[start:i] at each '\n' gives
+	// the empty string between newlines → 3 empty segments.
+	// (No trailing segment because start == len(s) at the end.)
+	if len(got) != 3 {
+		t.Errorf("only newlines: got %v (len=%d), want 3 empty strings", got, len(got))
+	}
+	for i, s := range got {
+		if s != "" {
+			t.Errorf("got[%d]=%q, want empty string", i, s)
+		}
+	}
+}
+
+func TestSplitLines_MultipleConsecutiveNewlines(t *testing.T) {
+	got := splitLines("a\n\n\nb")
+	// a\n\n\nb → ["a", "", "", "b"]
+	if len(got) != 4 {
+		t.Errorf("consecutive newlines: got %v (len=%d)", got, len(got))
+	}
+	if got[0] != "a" || got[3] != "b" {
+		t.Errorf("first/last: got %v, want [a, ..., b]", got)
+	}
+}
+
+// ---------------------------------------------------------------------------
+// findConfigDir
+// ---------------------------------------------------------------------------
+
+func TestFindConfigDir_NameMatch(t *testing.T) {
+	tmp := t.TempDir()
+
+	// Create two sub-dirs; only the one with matching name should be found.
+	mustMkdir(filepath.Join(tmp, "workspace-a"))
+	mustWrite(filepath.Join(tmp, "workspace-a", "config.yaml"),
+		"name: other-workspace\ntier: 1\n")
+
+	mustMkdir(filepath.Join(tmp, "workspace-b"))
+	mustWrite(filepath.Join(tmp, "workspace-b", "config.yaml"),
+		"name: target-workspace\nruntime: claude-code\n")
+
+	got := findConfigDir(tmp, "target-workspace")
+	want := filepath.Join(tmp, "workspace-b")
+	if got != want {
+		t.Errorf("got %q, want %q", got, want)
+	}
+}
+
+func TestFindConfigDir_NoMatch_UsesFallback(t *testing.T) {
+	tmp := t.TempDir()
+
+	mustMkdir(filepath.Join(tmp, "first"))
+	mustWrite(filepath.Join(tmp, "first", "config.yaml"), "name: workspace-a\n")
+
+	mustMkdir(filepath.Join(tmp, "second"))
+	mustWrite(filepath.Join(tmp, "second", "config.yaml"), "name: workspace-b\n")
+
+	// No exact name match → fallback to the first directory with a config.yaml.
+	got := findConfigDir(tmp, "nonexistent")
+	want := filepath.Join(tmp, "first")
+	if got != want {
+		t.Errorf("no match: got %q, want fallback %q", got, want)
+	}
+}
+
+func TestFindConfigDir_MissingDir(t *testing.T) {
+	got := findConfigDir("/nonexistent/path/for/findConfigDir", "any-name")
+	if got != "" {
+		t.Errorf("missing dir: got %q, want empty string", got)
+	}
+}
+
+func TestFindConfigDir_NoSubdirs(t *testing.T) {
+	tmp := t.TempDir()
+	// Empty directory → no matches, no fallback.
+	got := findConfigDir(tmp, "any")
+	if got != "" {
+		t.Errorf("empty dir: got %q, want empty string", got)
+	}
+}
+
+// ---------------------------------------------------------------------------
+// Helpers
+// ---------------------------------------------------------------------------
+
+func mustMkdir(path string) {
+	os.MkdirAll(path, 0o755)
+}
+
+func mustWrite(path, content string) {
+	os.WriteFile(path, []byte(content), 0o644)
+}
+
+// ---------------------------------------------------------------------------
+// findConfigDir
+// ---------------------------------------------------------------------------
+
+func TestFindConfigDir_SubdirWithoutConfig(t *testing.T) {
+	tmp := t.TempDir()
+	mustMkdir(filepath.Join(tmp, "empty-skill"))
+	// Sub-dir without config.yaml → skipped.
+	got := findConfigDir(tmp, "any")
+	if got != "" {
+		t.Errorf("no config.yaml: got %q, want empty string", got)
+	}
+}
+
+func TestFindConfigDir_FirstWithConfigIsFallback(t *testing.T) {
+	// When name doesn't match, fallback is the FIRST dir with config.yaml,
+	// not the last. Confirm ordering by creating three dirs.
+	tmp := t.TempDir()
+
+	mustMkdir(filepath.Join(tmp, "a"))
+	mustWrite(filepath.Join(tmp, "a", "config.yaml"), "name: alpha\n")
+
+	mustMkdir(filepath.Join(tmp, "b"))
+	mustWrite(filepath.Join(tmp, "b", "config.yaml"), "name: beta\n")
+
+	mustMkdir(filepath.Join(tmp, "c"))
+	mustWrite(filepath.Join(tmp, "c", "config.yaml"), "name: gamma\n")
+
+	got := findConfigDir(tmp, "nonexistent")
+	want := filepath.Join(tmp, "a") // first dir with config.yaml
+	if got != want {
+		t.Errorf("fallback order: got %q, want first-with-config %q", got, want)
+	}
+}

workspace-server/internal/bundle/importer_test.go

@@ -0,0 +1,157 @@
+package bundle
+
+import (
+	"testing"
+)
+
+func TestBuildBundleConfigFiles_emptyBundle(t *testing.T) {
+	b := &Bundle{}
+	files := buildBundleConfigFiles(b)
+	if len(files) != 0 {
+		t.Errorf("expected empty map for empty bundle, got %d entries", len(files))
+	}
+}
+
+func TestBuildBundleConfigFiles_systemPrompt(t *testing.T) {
+	b := &Bundle{SystemPrompt: "You are a helpful assistant."}
+	files := buildBundleConfigFiles(b)
+	if len(files) != 1 {
+		t.Fatalf("expected 1 file, got %d", len(files))
+	}
+	if string(files["system-prompt.md"]) != "You are a helpful assistant." {
+		t.Errorf("unexpected system prompt content: %q", files["system-prompt.md"])
+	}
+}
+
+func TestBuildBundleConfigFiles_configYaml(t *testing.T) {
+	b := &Bundle{Prompts: map[string]string{
+		"config.yaml": "runtime: langgraph\nmodel: claude-sonnet-4-20250514\n",
+	}}
+	files := buildBundleConfigFiles(b)
+	if len(files) != 1 {
+		t.Fatalf("expected 1 file, got %d", len(files))
+	}
+	if string(files["config.yaml"]) != "runtime: langgraph\nmodel: claude-sonnet-4-20250514\n" {
+		t.Errorf("unexpected config.yaml content: %q", files["config.yaml"])
+	}
+}
+
+func TestBuildBundleConfigFiles_systemPromptAndConfigYaml(t *testing.T) {
+	b := &Bundle{
+		SystemPrompt: "# System",
+		Prompts:     map[string]string{"config.yaml": "runtime: langgraph"},
+	}
+	files := buildBundleConfigFiles(b)
+	if len(files) != 2 {
+		t.Fatalf("expected 2 files, got %d", len(files))
+	}
+	if _, ok := files["system-prompt.md"]; !ok {
+		t.Error("missing system-prompt.md")
+	}
+	if _, ok := files["config.yaml"]; !ok {
+		t.Error("missing config.yaml")
+	}
+}
+
+func TestBuildBundleConfigFiles_skills(t *testing.T) {
+	b := &Bundle{
+		Skills: []BundleSkill{
+			{
+				ID:          "web-search",
+				Name:        "Web Search",
+				Description: "Search the web",
+				Files:       map[string]string{"readme.md": "# Web Search"},
+			},
+			{
+				ID:          "code-runner",
+				Name:        "Code Runner",
+				Description: "Execute code",
+				Files:       map[string]string{"handler.py": "print('hello')"},
+			},
+		},
+	}
+	files := buildBundleConfigFiles(b)
+	if len(files) != 2 {
+		t.Fatalf("expected 2 skill files, got %d", len(files))
+	}
+
+	if content, ok := files["skills/web-search/readme.md"]; !ok {
+		t.Error("missing skills/web-search/readme.md")
+	} else if string(content) != "# Web Search" {
+		t.Errorf("unexpected readme.md: %q", content)
+	}
+
+	if _, ok := files["skills/code-runner/handler.py"]; !ok {
+		t.Error("missing skills/code-runner/handler.py")
+	}
+}
+
+func TestBuildBundleConfigFiles_skillsWithSubPaths(t *testing.T) {
+	b := &Bundle{
+		Skills: []BundleSkill{
+			{
+				ID:    "nested-skill",
+				Files: map[string]string{"src/main.py": "def main(): pass", "pyproject.toml": "[tool.foo]"},
+			},
+		},
+	}
+	files := buildBundleConfigFiles(b)
+	if len(files) != 2 {
+		t.Fatalf("expected 2 files, got %d", len(files))
+	}
+	if _, ok := files["skills/nested-skill/src/main.py"]; !ok {
+		t.Error("missing skills/nested-skill/src/main.py")
+	}
+	if _, ok := files["skills/nested-skill/pyproject.toml"]; !ok {
+		t.Error("missing skills/nested-skill/pyproject.toml")
+	}
+}
+
+func TestBuildBundleConfigFiles_skipsEmptyPrompts(t *testing.T) {
+	b := &Bundle{Prompts: map[string]string{}}
+	files := buildBundleConfigFiles(b)
+	if len(files) != 0 {
+		t.Errorf("expected 0 files for empty prompts map, got %d", len(files))
+	}
+}
+
+func TestBuildBundleConfigFiles_skipsMissingConfigYaml(t *testing.T) {
+	b := &Bundle{
+		SystemPrompt: "# My Prompt",
+		Prompts:      map[string]string{"other.yaml": "something: else"},
+	}
+	files := buildBundleConfigFiles(b)
+	if len(files) != 1 {
+		t.Fatalf("expected 1 file (system-prompt only), got %d", len(files))
+	}
+	if _, ok := files["config.yaml"]; ok {
+		t.Error("config.yaml should not be written when not in Prompts")
+	}
+}
+
+func TestNilIfEmpty_emptyString(t *testing.T) {
+	result := nilIfEmpty("")
+	if result != nil {
+		t.Errorf("expected nil for empty string, got %v", result)
+	}
+}
+
+func TestNilIfEmpty_nonEmptyString(t *testing.T) {
+	result := nilIfEmpty("hello")
+	if result == nil {
+		t.Fatal("expected non-nil result for non-empty string")
+	}
+	if result != "hello" {
+		t.Errorf("expected hello, got %q", result)
+	}
+}
+
+func TestNilIfEmpty_whitespaceString(t *testing.T) {
+	// Whitespace is not empty — nilIfEmpty only checks for zero-length
+	result := nilIfEmpty("   ")
+	if result == nil {
+		t.Error("expected non-nil for whitespace string")
+	} else if result != "   " {
+		t.Errorf("expected '   ', got %q", result)
+	}
+}