feat(pierre): add diff chunking and configurable review settings

internal/pierre/judge_test.go

@@ -0,0 +1,132 @@
+package pierre
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"strings"
+	"testing"
+
+	"git.schreifuchs.ch/schreifuchs/pierre-bot/internal/chatter"
+	"github.com/google/go-cmp/cmp"
+)
+
+// mockChat implements the ChatAdapter interface for testing.
+type mockChat struct{ callCount int }
+
+func (m *mockChat) GenerateStructured(ctx context.Context, msgs []chatter.Message, target interface{}) error {
+	m.callCount++
+	if cSlice, ok := target.(*[]Comment); ok {
+		*cSlice = []Comment{{File: "file.go", Line: 1, Message: "test comment"}}
+		return nil
+	}
+	return nil
+}
+
+func (m *mockChat) GetProviderName() string { return "mock" }
+
+// mockGit implements the GitAdapter interface for testing.
+type mockGit struct{}
+
+func (g *mockGit) GetDiff(ctx context.Context, owner, repo string, prID int) (io.ReadCloser, error) {
+	diff := "diff --git a/file1.go b/file1.go\n+line1\n" + "diff --git a/file2.go b/file2.go\n+line2\n"
+	return io.NopCloser(bytes.NewReader([]byte(diff))), nil
+}
+
+func (g *mockGit) AddComment(ctx context.Context, owner, repo string, prID int, comment Comment) error {
+	return nil
+}
+
+func TestSplitDiffIntoChunks(t *testing.T) {
+	cases := []struct {
+		name           string
+		diff           string
+		maxSize        int
+		wantChunks     int // 0 means we don't assert exact count
+		wantPrefixes   []string
+		checkRecombine bool
+	}{
+		{
+			name:           "small diff",
+			diff:           "diff --git a/file1.txt b/file1.txt\n+added line\n",
+			maxSize:        1000,
+			wantChunks:     1,
+			wantPrefixes:   []string{"diff --git a/file1.txt"},
+			checkRecombine: true,
+		},
+		{
+			name: "multiple files",
+			diff: "diff --git a/file1.txt b/file1.txt\n+added line 1\n" +
+				"diff --git a/file2.txt b/file2.txt\n+added line 2\n",
+			maxSize:        50,
+			wantChunks:     2,
+			wantPrefixes:   []string{"diff --git a/file1.txt", "diff --git a/file2.txt"},
+			checkRecombine: false,
+		},
+		{
+			name: "large single file",
+			diff: func() string {
+				line := "+very long added line that will be repeated many times to exceed the chunk size\n"
+				return "diff --git a/large.txt b/large.txt\n" + strings.Repeat(line, 200)
+			}(),
+			maxSize:        500,
+			wantChunks:     0,
+			wantPrefixes:   nil,
+			checkRecombine: true,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			chunks := splitDiffIntoChunks([]byte(tc.diff), tc.maxSize)
+			if tc.wantChunks > 0 && len(chunks) != tc.wantChunks {
+				t.Fatalf("expected %d chunks, got %d", tc.wantChunks, len(chunks))
+			}
+			for i, prefix := range tc.wantPrefixes {
+				if i >= len(chunks) {
+					t.Fatalf("missing chunk %d for prefix check", i)
+				}
+				trimmed := strings.TrimPrefix(chunks[i], "\n")
+				if !strings.HasPrefix(trimmed, prefix) {
+					t.Fatalf("chunk %d does not start with expected prefix %q: %s", i, prefix, chunks[i])
+				}
+			}
+			for i, c := range chunks {
+				if tc.maxSize > 0 && len(c) > tc.maxSize {
+					t.Fatalf("chunk %d exceeds max size %d: %d", i, tc.maxSize, len(c))
+				}
+			}
+			if tc.checkRecombine {
+				recombined := strings.Join(chunks, "")
+				if diff := cmp.Diff(tc.diff, recombined); diff != "" {
+					t.Fatalf("recombined diff differs:\n%s", diff)
+				}
+			}
+		})
+	}
+}
+
+func TestJudgePR_ChunkAggregationAndDeduplication(t *testing.T) {
+	chatMock := &mockChat{}
+	svc := &Service{
+		maxChunkSize: 50,
+		guidelines:   nil,
+		git:          &mockGit{},
+		chat:         chatMock,
+	}
+	diffReader, err := svc.git.GetDiff(context.Background(), "", "", 0)
+	if err != nil {
+		t.Fatalf("failed to get diff: %v", err)
+	}
+	defer diffReader.Close()
+	comments, err := svc.judgePR(context.Background(), diffReader)
+	if err != nil {
+		t.Fatalf("judgePR error: %v", err)
+	}
+	if got, want := len(comments), 1; got != want {
+		t.Fatalf("expected %d comment after deduplication, got %d", want, got)
+	}
+	if chatMock.callCount != 2 {
+		t.Fatalf("expected mockChat to be called for each chunk (2), got %d", chatMock.callCount)
+	}
+}