test(gitea): add hunk-header-at-end error path test

Adds TestTranslate_HunkHeaderAtEnd covering the edge case where a
hunk-header is the last position in the file with no subsequent
new-file line. Mirrors TestBuildPositionToLineMap_DeletionAtEnd for
the hunk-header code path.

Addresses NIT from sonnet-review-bot on PR #104 (comment 18412).

.gitea/actions/review/action.yml

@@ -104,10 +104,6 @@ inputs:
     description: 'Path to custom persona JSON file'
     required: false
     default: ''
-  action-repo:
-    description: 'Repository hosting the review-bot binary (owner/name). Defaults to rodin/review-bot on Gitea, or strat/review-bot on GitHub.'
-    required: false
-    default: ''
 
 runs:
   using: 'composite'
@@ -116,21 +112,10 @@ runs:
       id: version
       shell: bash
       run: |
-        SERVER_URL="${{ inputs.gitea-url || github.server_url }}"
+        GITEA_URL="${{ inputs.gitea-url || github.server_url }}"
-        # Detect VCS type: Gitea uses /api/v1/, GitHub uses /api/v3/
+        REPO="${{ inputs.repo || 'rodin/review-bot' }}"
-        if echo "$SERVER_URL" | grep -qi 'gitea'; then
-          API_BASE="${SERVER_URL}/api/v1"
-          DEFAULT_ACTION_REPO="rodin/review-bot"
-        else
-          API_BASE="${SERVER_URL}/api/v3"
-          DEFAULT_ACTION_REPO="strat/review-bot"
-        fi
-        ACTION_REPO="${{ inputs.action-repo || '' }}"
-        if [ -z "$ACTION_REPO" ]; then
-          ACTION_REPO="$DEFAULT_ACTION_REPO"
-        fi
         if [ "${{ inputs.version }}" = "latest" ]; then
-          VERSION=$(curl -sSf "${API_BASE}/repos/${ACTION_REPO}/releases?limit=1" \
+          VERSION=$(curl -sSf "${GITEA_URL}/api/v1/repos/${REPO}/releases?limit=1" \
             | python3 -c "import sys, json; releases = json.load(sys.stdin); print(releases[0]['tag_name'] if releases else '')")
           if [ -z "$VERSION" ]; then
             echo "Failed to determine latest version" >&2
@@ -140,8 +125,6 @@ runs:
           VERSION="${{ inputs.version }}"
         fi
         echo "version=${VERSION}" >> "$GITHUB_OUTPUT"
-        echo "action-repo=${ACTION_REPO}" >> "$GITHUB_OUTPUT"
-        echo "server-url=${SERVER_URL}" >> "$GITHUB_OUTPUT"
 
     - name: Cache review-bot binary
       id: cache
@@ -154,14 +137,14 @@ runs:
       if: steps.cache.outputs.cache-hit != 'true'
       shell: bash
       run: |
-        SERVER_URL="${{ steps.version.outputs.server-url }}"
+        GITEA_URL="${{ inputs.gitea-url || github.server_url }}"
-        ACTION_REPO="${{ steps.version.outputs.action-repo }}"
+        REPO="${{ inputs.repo || 'rodin/review-bot' }}"
         VERSION="${{ steps.version.outputs.version }}"
         BINARY="review-bot-linux-amd64"
 
-        curl -sSfL "${SERVER_URL}/${ACTION_REPO}/releases/download/${VERSION}/${BINARY}" \
+        curl -sSfL "${GITEA_URL}/${REPO}/releases/download/${VERSION}/${BINARY}" \
           -o "${{ runner.temp }}/review-bot"
-        curl -sSfL "${SERVER_URL}/${ACTION_REPO}/releases/download/${VERSION}/checksums.txt" \
+        curl -sSfL "${GITEA_URL}/${REPO}/releases/download/${VERSION}/checksums.txt" \
           -o "${{ runner.temp }}/checksums.txt"
 
         # Verify SHA-256 checksum
@@ -186,8 +169,8 @@ runs:
     - name: Run review
       shell: bash
       env:
-        GITHUB_SERVER_URL: ${{ inputs.gitea-url || github.server_url }}
+        GITEA_URL: ${{ inputs.gitea-url || github.server_url }}
-        GITHUB_REPOSITORY: ${{ inputs.repo || github.repository }}
+        GITEA_REPO: ${{ inputs.repo || github.repository }}
         PR_NUMBER: ${{ inputs.pr-number || github.event.pull_request.number }}
         REVIEWER_TOKEN: ${{ inputs.reviewer-token }}
         REVIEWER_NAME: ${{ inputs.reviewer-name }}

.github/actions/review/action.yml

@@ -104,10 +104,6 @@ inputs:
     description: 'Path to custom persona JSON file'
     required: false
     default: ''
-  action-repo:
-    description: 'Repository hosting the review-bot binary (owner/name). Defaults to rodin/review-bot on Gitea, or strat/review-bot on GitHub.'
-    required: false
-    default: ''
 
 runs:
   using: 'composite'
@@ -116,21 +112,10 @@ runs:
       id: version
       shell: bash
       run: |
-        SERVER_URL="${{ inputs.gitea-url || github.server_url }}"
+        GITEA_URL="${{ inputs.gitea-url || github.server_url }}"
-        # Detect VCS type: Gitea uses /api/v1/, GitHub uses /api/v3/
+        REPO="${{ inputs.repo || 'rodin/review-bot' }}"
-        if echo "$SERVER_URL" | grep -qi 'gitea'; then
-          API_BASE="${SERVER_URL}/api/v1"
-          DEFAULT_ACTION_REPO="rodin/review-bot"
-        else
-          API_BASE="${SERVER_URL}/api/v3"
-          DEFAULT_ACTION_REPO="strat/review-bot"
-        fi
-        ACTION_REPO="${{ inputs.action-repo || '' }}"
-        if [ -z "$ACTION_REPO" ]; then
-          ACTION_REPO="$DEFAULT_ACTION_REPO"
-        fi
         if [ "${{ inputs.version }}" = "latest" ]; then
-          VERSION=$(curl -sSf "${API_BASE}/repos/${ACTION_REPO}/releases?limit=1" \
+          VERSION=$(curl -sSf "${GITEA_URL}/api/v1/repos/${REPO}/releases?limit=1" \
             | python3 -c "import sys, json; releases = json.load(sys.stdin); print(releases[0]['tag_name'] if releases else '')")
           if [ -z "$VERSION" ]; then
             echo "Failed to determine latest version" >&2
@@ -140,8 +125,6 @@ runs:
           VERSION="${{ inputs.version }}"
         fi
         echo "version=${VERSION}" >> "$GITHUB_OUTPUT"
-        echo "action-repo=${ACTION_REPO}" >> "$GITHUB_OUTPUT"
-        echo "server-url=${SERVER_URL}" >> "$GITHUB_OUTPUT"
 
     - name: Cache review-bot binary
       id: cache
@@ -154,14 +137,14 @@ runs:
       if: steps.cache.outputs.cache-hit != 'true'
       shell: bash
       run: |
-        SERVER_URL="${{ steps.version.outputs.server-url }}"
+        GITEA_URL="${{ inputs.gitea-url || github.server_url }}"
-        ACTION_REPO="${{ steps.version.outputs.action-repo }}"
+        REPO="${{ inputs.repo || 'rodin/review-bot' }}"
         VERSION="${{ steps.version.outputs.version }}"
         BINARY="review-bot-linux-amd64"
 
-        curl -sSfL "${SERVER_URL}/${ACTION_REPO}/releases/download/${VERSION}/${BINARY}" \
+        curl -sSfL "${GITEA_URL}/${REPO}/releases/download/${VERSION}/${BINARY}" \
           -o "${{ runner.temp }}/review-bot"
-        curl -sSfL "${SERVER_URL}/${ACTION_REPO}/releases/download/${VERSION}/checksums.txt" \
+        curl -sSfL "${GITEA_URL}/${REPO}/releases/download/${VERSION}/checksums.txt" \
           -o "${{ runner.temp }}/checksums.txt"
 
         # Verify SHA-256 checksum

.github/workflows/review.yml

@@ -1,47 +0,0 @@
-# Self-review workflow for strat/review-bot on GitHub Enterprise Server.
-# Tests that the composite action runs correctly on GitHub runners:
-# - GITHUB_SERVER_URL and GITHUB_REPOSITORY env vars are set correctly
-# - Binary is downloaded from gitea.weiker.me (where releases live)
-# - Review is posted to the corresponding Gitea PR
-name: Review
-
-on:
-  pull_request:
-    types: [opened, synchronize]
-
-jobs:
-  review:
-    runs-on: ubuntu-24.04
-    if: github.event_name == 'pull_request'
-    strategy:
-      matrix:
-        include:
-          - name: sonnet
-            token_secret: SONNET_REVIEW_TOKEN
-            model: anthropic--claude-4.6-sonnet
-          - name: gpt
-            token_secret: GPT_REVIEW_TOKEN
-            model: gpt-5
-    steps:
-      - uses: actions/checkout@v4
-      - name: Run ${{ matrix.name }} review
-        uses: ./.gitea/actions/review
-        with:
-          # Download binary from Gitea (releases live there, not on GHE)
-          gitea-url: https://gitea.weiker.me
-          # Post review to the corresponding Gitea repo
-          repo: rodin/review-bot
-          reviewer-token: ${{ secrets[matrix.token_secret] }}
-          reviewer-name: ${{ matrix.name }}
-          llm-model: ${{ matrix.model }}
-          llm-provider: aicore
-          aicore-client-id: ${{ secrets.AICORE_CLIENT_ID }}
-          aicore-client-secret: ${{ secrets.AICORE_CLIENT_SECRET }}
-          aicore-auth-url: ${{ secrets.AICORE_AUTH_URL }}
-          aicore-api-url: ${{ secrets.AICORE_API_URL }}
-          aicore-resource-group: ${{ secrets.AICORE_RESOURCE_GROUP }}
-          conventions-file: CONVENTIONS.md
-          patterns-repo: rodin/go-patterns
-          patterns-files: 'README.md,patterns/'
-          dry-run: 'true'
-          timeout: '600'

gitea/position.go

@@ -11,6 +11,7 @@ import (
 type PositionMap struct {
 	// files maps filename → (position → new-file line number).
 	// Deletion lines are mapped to -1 (no new-file line).
+	// Hunk-header lines are mapped to 0 (no new-file line).
 	files map[string]map[int]int
 	// maxPositions caches the highest position number per file,
 	// tracked during construction to avoid O(n) scans at translate time.
@@ -19,8 +20,8 @@ type PositionMap struct {
 
 // Translate converts a GitHub diff-position to a new-file line number for a given file.
 // Returns an error if the file is not in the diff or the position is out of range.
-// If the position targets a deletion line, it maps to the nearest non-deletion line below;
+// If the position targets a deletion or hunk-header line, it maps to the nearest
-// if no such line exists, returns an error.
+// context/addition line below; if no such line exists, returns an error.
 func (pm *PositionMap) Translate(file string, position int) (int, error) {
 	if pm == nil || pm.files == nil {
 		return 0, fmt.Errorf("empty position map")
@@ -41,14 +42,18 @@ func (pm *PositionMap) Translate(file string, position int) (int, error) {
 	}
 
 	// lineNum == -1 means this position is a deletion line.
-	// Map to the nearest non-deletion line below.
+	// lineNum == 0 means this position is a hunk-header line.
-	if lineNum == -1 {
+	// Both map to the nearest context/addition line below.
+	if lineNum <= 0 {
 		maxPos := pm.maxPosition(file)
 		for p := position + 1; p <= maxPos; p++ {
 			if ln, exists := fileMap[p]; exists && ln > 0 {
 				return ln, nil
 			}
 		}
+		if lineNum == 0 {
+			return 0, fmt.Errorf("position %d targets a hunk-header line with no subsequent new-file line in %q", position, file)
+		}
 		return 0, fmt.Errorf("position %d targets a deletion line with no subsequent new-file line in %q", position, file)
 	}
 
@@ -70,6 +75,7 @@ func (pm *PositionMap) maxPosition(file string) int {
 //   - A new @@ hunk within the same file continues incrementing (does not reset)
 //   - Position maps to the new file line number for additions and context lines
 //   - Deletion lines have a position but no new-file line number (stored as -1)
+//   - Hunk-header lines have a position but no new-file line number (stored as 0)
 func BuildPositionToLineMap(diff string) *PositionMap {
 	pm := &PositionMap{
 		files:        make(map[string]map[int]int),
@@ -126,6 +132,7 @@ func BuildPositionToLineMap(diff string) *PositionMap {
 		// Parse hunk headers
 		if strings.HasPrefix(line, "@@") && currentFile != "" {
 			position++
+			pm.files[currentFile][position] = 0 // sentinel: hunk-header has no new-file line
 			pm.maxPositions[currentFile] = position
 			newLine = parseHunkStart(line)
 			continue

gitea/position_test.go

@@ -272,3 +272,112 @@ diff --git a/b.go b/b.go
 		t.Errorf("Translate(b.go, 3) = %d, want 2", got)
 	}
 }
+
+func TestTranslate_HunkHeaderPosition_SingleHunk(t *testing.T) {
+	// Position 1 is the @@ hunk-header line.
+	// It should resolve to the first context/addition line below (new line 16).
+	diff := `diff --git a/file.go b/file.go
+index abc..def 100644
+--- a/file.go
++++ b/file.go
+@@ -16,4 +16,5 @@ func example() {
+ context line
+-deleted line
++added line
+ context after
+`
+	pm := BuildPositionToLineMap(diff)
+
+	got, err := pm.Translate("file.go", 1)
+	if err != nil {
+		t.Fatalf("Translate(file.go, 1): unexpected error: %v", err)
+	}
+	if got != 16 {
+		t.Errorf("Translate(file.go, 1) = %d, want 16 (first context/addition line in hunk)", got)
+	}
+}
+
+func TestTranslate_HunkHeaderPosition_MultiHunk(t *testing.T) {
+	// First hunk: @@ is pos 1, then " line1" (pos 2), "-old" (pos 3), "+new" (pos 4)
+	// Second hunk: @@ is pos 5, then " func foo() {" (pos 6), "+// added" (pos 7), etc.
+	// Translating position 5 (second @@) should resolve to new line 10.
+	diff := `diff --git a/file.go b/file.go
+--- a/file.go
++++ b/file.go
+@@ -1,3 +1,3 @@ package main
+ line1
+-old
++new
+@@ -10,3 +10,4 @@ func foo() {
+ func foo() {
++	// added
+ 	return
+ }
+`
+	pm := BuildPositionToLineMap(diff)
+
+	// Position 5 is the second @@ hunk-header — should resolve to new line 10
+	got, err := pm.Translate("file.go", 5)
+	if err != nil {
+		t.Fatalf("Translate(file.go, 5): unexpected error: %v", err)
+	}
+	if got != 10 {
+		t.Errorf("Translate(file.go, 5) = %d, want 10 (first context/addition line in second hunk)", got)
+	}
+
+	// Also verify first hunk header at position 1 resolves to new line 1
+	got, err = pm.Translate("file.go", 1)
+	if err != nil {
+		t.Fatalf("Translate(file.go, 1): unexpected error: %v", err)
+	}
+	if got != 1 {
+		t.Errorf("Translate(file.go, 1) = %d, want 1 (first context/addition line in first hunk)", got)
+	}
+}
+
+func TestTranslate_HunkHeaderPosition_NewFile(t *testing.T) {
+	// New file: @@ -0,0 +1,3 @@ is position 1.
+	// Should resolve to new line 1 (the first addition).
+	diff := `diff --git a/new.go b/new.go
+new file mode 100644
+--- /dev/null
++++ b/new.go
+@@ -0,0 +1,3 @@
++package main
++
++func init() {}
+`
+	pm := BuildPositionToLineMap(diff)
+
+	got, err := pm.Translate("new.go", 1)
+	if err != nil {
+		t.Fatalf("Translate(new.go, 1): unexpected error: %v", err)
+	}
+	if got != 1 {
+		t.Errorf("Translate(new.go, 1) = %d, want 1 (first addition line)", got)
+	}
+}
+
+func TestTranslate_HunkHeaderAtEnd(t *testing.T) {
+	// A hunk-header at the last position with no subsequent new-file line should error.
+	// This is the hunk-header equivalent of TestBuildPositionToLineMap_DeletionAtEnd.
+	diff := `diff --git a/file.go b/file.go
+--- a/file.go
++++ b/file.go
+@@ -1,2 +1,2 @@ package main
+ line1
+-old
++new
+@@ -10,2 +10,1 @@ func foo() {
+-removed
+`
+	pm := BuildPositionToLineMap(diff)
+
+	// Position 5 is the second @@ hunk-header; the only line after it (pos 6) is a
+	// deletion (lineNum == -1), so there's no positive new-file line to resolve to.
+	// The hunk-header lookup should fail.
+	_, err := pm.Translate("file.go", 5)
+	if err == nil {
+		t.Error("expected error for hunk-header at end with no subsequent new-file line")
+	}
+}

github/conformance_test.go

@@ -5,6 +5,9 @@ import (
 	"gitea.weiker.me/rodin/review-bot/vcs"
 )
 
-// Compile-time interface conformance assertion.
+// Compile-time interface conformance assertions.
-// Verifies github.Client satisfies vcs.PRReader.
+// These verify github.Client satisfies vcs.PRReader and vcs.FileReader.
-var _ vcs.PRReader = (*github.Client)(nil)
+var (
+	_ vcs.PRReader   = (*github.Client)(nil)
+	_ vcs.FileReader = (*github.Client)(nil)
+)

github/files.go

@@ -8,8 +8,16 @@ import (
 	"net/url"
 	"path"
 	"strings"
+
+	"gitea.weiker.me/rodin/review-bot/vcs"
 )
 
+// GetFileContent fetches a file from a repo at the given ref.
+// Delegates to GetFileContentAtRef with the provided ref.
+func (c *Client) GetFileContent(ctx context.Context, owner, repo, filePath, ref string) (string, error) {
+	return c.GetFileContentAtRef(ctx, owner, repo, filePath, ref)
+}
+
 // GetFileContentAtRef fetches a file at a specific ref from a repo.
 // If ref is empty, the query parameter is omitted (uses default branch).
 //
@@ -46,6 +54,58 @@ func (c *Client) GetFileContentAtRef(ctx context.Context, owner, repo, filePath,
 	return decoded, nil
 }
 
+// ListContents lists files and directories at a given path in a repo.
+// Returns the directory listing from the GitHub contents API.
+// If the path points to a single file (not a directory), the API returns
+// a JSON object instead of an array; this is handled by returning a
+// single-element slice.
+func (c *Client) ListContents(ctx context.Context, owner, repo, filePath string) ([]vcs.ContentEntry, error) {
+	escaped, err := escapePath(filePath)
+	if err != nil {
+		return nil, fmt.Errorf("invalid file path: %w", err)
+	}
+	reqURL := fmt.Sprintf("%s/repos/%s/%s/contents/%s",
+		c.baseURL, url.PathEscape(owner), url.PathEscape(repo), escaped)
+	body, err := c.doGet(ctx, reqURL)
+	if err != nil {
+		return nil, fmt.Errorf("list contents %s: %w", filePath, err)
+	}
+
+	type entry struct {
+		Name string `json:"name"`
+		Path string `json:"path"`
+		Type string `json:"type"`
+	}
+
+	// The GitHub contents API returns an array for directories and an object
+	// for single files. Try array first (common case), then fall back to object.
+	// An empty array ([]) is valid — it represents an empty directory — and
+	// results in a zero-length slice returned without error.
+	var entries []entry
+	if err := json.Unmarshal(body, &entries); err != nil {
+		var single entry
+		if err2 := json.Unmarshal(body, &single); err2 != nil {
+			return nil, fmt.Errorf("parse contents JSON: as array: %v; as object: %w", err, err2)
+		}
+		// Guard against empty objects ({}) or unexpected shapes that
+		// unmarshal successfully but carry no useful data.
+		if single.Name == "" && single.Path == "" && single.Type == "" {
+			return nil, fmt.Errorf("parse contents JSON: unexpected response format")
+		}
+		entries = []entry{single}
+	}
+
+	result := make([]vcs.ContentEntry, len(entries))
+	for i, e := range entries {
+		result[i] = vcs.ContentEntry{
+			Name: e.Name,
+			Path: e.Path,
+			Type: e.Type,
+		}
+	}
+	return result, nil
+}
+
 // escapePath validates and encodes a slash-separated file path for use in
 // GitHub API URLs. Returns an error if the path contains dot-segments ("."
 // or "..") or resolves to a path outside the repository root.

github/files_test.go

@@ -2,12 +2,291 @@ package github
 
 import (
 	"context"
+	"encoding/json"
 	"net/http"
 	"net/http/httptest"
 	"strings"
 	"testing"
+	"time"
 )
 
+func TestGetFileContent_DelegatesToGetFileContentAtRef(t *testing.T) {
+	var gotRef string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotRef = r.URL.Query().Get("ref")
+		json.NewEncoder(w).Encode(map[string]string{
+			"content":  "dGVzdA==", // "test" in base64
+			"encoding": "base64",
+		})
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	// Call with empty ref — should not include ref param
+	content, err := c.GetFileContent(context.Background(), "owner", "repo", "file.go", "")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if content != "test" {
+		t.Errorf("expected 'test', got %q", content)
+	}
+	if gotRef != "" {
+		t.Errorf("expected empty ref, got %q", gotRef)
+	}
+}
+
+func TestGetFileContent_WithRef(t *testing.T) {
+	var gotRef string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotRef = r.URL.Query().Get("ref")
+		json.NewEncoder(w).Encode(map[string]string{
+			"content":  "dGVzdA==",
+			"encoding": "base64",
+		})
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetFileContent(context.Background(), "owner", "repo", "file.go", "abc123")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if gotRef != "abc123" {
+		t.Errorf("expected ref 'abc123', got %q", gotRef)
+	}
+}
+
+func TestGetFileContent_404(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(404)
+		w.Write([]byte(`{"message":"Not Found"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetFileContent(context.Background(), "owner", "repo", "missing.go", "")
+	if err == nil {
+		t.Fatal("expected error for 404")
+	}
+}
+
+func TestGetFileContent_401(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(401)
+		w.Write([]byte(`{"message":"Bad credentials"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetFileContent(context.Background(), "owner", "repo", "file.go", "")
+	if err == nil {
+		t.Fatal("expected error for 401")
+	}
+}
+
+func TestGetFileContent_429Retry(t *testing.T) {
+	attempts := 0
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		attempts++
+		if attempts == 1 {
+			w.WriteHeader(429)
+			w.Write([]byte(`{"message":"rate limit"}`))
+			return
+		}
+		json.NewEncoder(w).Encode(map[string]string{
+			"content":  "b2s=",
+			"encoding": "base64",
+		})
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	if err := c.SetRetryBackoff([]time.Duration{1 * time.Millisecond, 1 * time.Millisecond}); err != nil {
+		t.Fatalf("SetRetryBackoff: %v", err)
+	}
+
+	content, err := c.GetFileContent(context.Background(), "owner", "repo", "file.go", "")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if content != "ok" {
+		t.Errorf("expected 'ok', got %q", content)
+	}
+	if attempts != 2 {
+		t.Errorf("expected 2 attempts, got %d", attempts)
+	}
+}
+
+func TestGetFileContent_MalformedJSON(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(200)
+		w.Write([]byte(`not json`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetFileContent(context.Background(), "owner", "repo", "file.go", "")
+	if err == nil {
+		t.Fatal("expected error for malformed JSON")
+	}
+}
+
+func TestListContents_HappyPath(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/repos/owner/repo/contents/src" {
+			t.Errorf("unexpected path: %s", r.URL.Path)
+		}
+		json.NewEncoder(w).Encode([]map[string]string{
+			{"name": "main.go", "path": "src/main.go", "type": "file"},
+			{"name": "lib", "path": "src/lib", "type": "dir"},
+		})
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	entries, err := c.ListContents(context.Background(), "owner", "repo", "src")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(entries) != 2 {
+		t.Fatalf("expected 2 entries, got %d", len(entries))
+	}
+	if entries[0].Name != "main.go" {
+		t.Errorf("expected name 'main.go', got %q", entries[0].Name)
+	}
+	if entries[0].Path != "src/main.go" {
+		t.Errorf("expected path 'src/main.go', got %q", entries[0].Path)
+	}
+	if entries[0].Type != "file" {
+		t.Errorf("expected type 'file', got %q", entries[0].Type)
+	}
+	if entries[1].Name != "lib" {
+		t.Errorf("expected name 'lib', got %q", entries[1].Name)
+	}
+	if entries[1].Type != "dir" {
+		t.Errorf("expected type 'dir', got %q", entries[1].Type)
+	}
+}
+
+func TestListContents_404(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(404)
+		w.Write([]byte(`{"message":"Not Found"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.ListContents(context.Background(), "owner", "repo", "missing")
+	if err == nil {
+		t.Fatal("expected error for 404")
+	}
+}
+
+func TestListContents_401(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(401)
+		w.Write([]byte(`{"message":"Bad credentials"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.ListContents(context.Background(), "owner", "repo", "src")
+	if err == nil {
+		t.Fatal("expected error for 401")
+	}
+}
+
+func TestListContents_429Retry(t *testing.T) {
+	attempts := 0
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		attempts++
+		if attempts == 1 {
+			w.WriteHeader(429)
+			w.Write([]byte(`{"message":"rate limit"}`))
+			return
+		}
+		json.NewEncoder(w).Encode([]map[string]string{
+			{"name": "file.go", "path": "file.go", "type": "file"},
+		})
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	if err := c.SetRetryBackoff([]time.Duration{1 * time.Millisecond, 1 * time.Millisecond}); err != nil {
+		t.Fatalf("SetRetryBackoff: %v", err)
+	}
+
+	entries, err := c.ListContents(context.Background(), "owner", "repo", "src")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(entries) != 1 {
+		t.Fatalf("expected 1 entry, got %d", len(entries))
+	}
+	if attempts != 2 {
+		t.Errorf("expected 2 attempts, got %d", attempts)
+	}
+}
+
+func TestListContents_MalformedJSON(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(200)
+		w.Write([]byte(`not json`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.ListContents(context.Background(), "owner", "repo", "src")
+	if err == nil {
+		t.Fatal("expected error for malformed JSON")
+	}
+}
+
+func TestListContents_SingleFile(t *testing.T) {
+	// GitHub Contents API returns a JSON object (not array) for single-file paths
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(200)
+		w.Write([]byte(`{"name":"README.md","path":"README.md","type":"file"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	entries, err := c.ListContents(context.Background(), "owner", "repo", "README.md")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(entries) != 1 {
+		t.Fatalf("expected 1 entry, got %d", len(entries))
+	}
+	if entries[0].Name != "README.md" {
+		t.Errorf("expected name 'README.md', got %q", entries[0].Name)
+	}
+	if entries[0].Type != "file" {
+		t.Errorf("expected type 'file', got %q", entries[0].Type)
+	}
+}
+
 func TestEscapePath_ValidPaths(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
@@ -68,7 +347,7 @@ func TestGetFileContentAtRef_DotSegmentError(t *testing.T) {
 	}))
 	defer srv.Close()
 
-	c := NewClient("token", srv.URL)
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
 	_, err := c.GetFileContentAtRef(context.Background(), "owner", "repo", "foo/../bar.go", "main")
 	if err == nil {
 		t.Fatal("expected error for path with dot-segments")
@@ -78,6 +357,37 @@ func TestGetFileContentAtRef_DotSegmentError(t *testing.T) {
 	}
 }
 
+func TestDecodeBase64Content(t *testing.T) {
+	// Test with newlines (GitHub's format)
+	encoded := "cGFja2FnZSBt\nYWlu"
+	decoded, err := decodeBase64Content(encoded)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if decoded != "package main" {
+		t.Errorf("expected 'package main', got %q", decoded)
+	}
+}
+
+func TestDecodeBase64Content_Invalid(t *testing.T) {
+	_, err := decodeBase64Content("not!!!valid!!!base64")
+	if err == nil {
+		t.Fatal("expected error for invalid base64")
+	}
+}
+
+func TestDecodeBase64Content_CRLF(t *testing.T) {
+	// Base64 of "hello world" with CRLF line breaks inserted
+	encoded := "aGVs\r\nbG8g\r\nd29y\r\nbGQ="
+	decoded, err := decodeBase64Content(encoded)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if decoded != "hello world" {
+		t.Errorf("expected 'hello world', got %q", decoded)
+	}
+}
+
 func TestDecodeBase64Content_SizeLimit(t *testing.T) {
 	t.Parallel()
 	// Create base64 content that would decode to > maxFileContentSize.
@@ -93,4 +403,3 @@ func TestDecodeBase64Content_SizeLimit(t *testing.T) {
 		t.Errorf("expected 'too large' error, got: %v", err)
 	}
 }
-