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

internal/pierre/judge_test.go

@@ -0,0 +1,57 @@
+package pierre
+
+import (
+	"github.com/google/go-cmp/cmp"
+	"strings"
+	"testing"
+)
+
+func TestSplitDiffIntoChunks_SmallDiff(t *testing.T) {
+	diff := "diff --git a/file1.txt b/file1.txt\n+added line\n"
+	max := 1000
+	chunks := splitDiffIntoChunks([]byte(diff), max)
+	if got, want := len(chunks), 1; got != want {
+		t.Fatalf("expected %d chunk, got %d", want, got)
+	}
+	if diff != chunks[0] {
+		t.Fatalf("chunk content changed: %s", diff)
+	}
+}
+
+func TestSplitDiffIntoChunks_MultipleFiles(t *testing.T) {
+	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"
+	max := 50 // each file diff is less than this, but total exceeds
+	chunks := splitDiffIntoChunks([]byte(diff), max)
+	if got, want := len(chunks), 2; got != want {
+		t.Fatalf("expected %d chunks, got %d", want, got)
+	}
+	// Ensure each chunk starts with the proper file header
+	if !strings.HasPrefix(chunks[0], "diff --git a/file1.txt") {
+		t.Fatalf("first chunk does not contain file1 header: %s", chunks[0])
+	}
+	if !strings.HasPrefix(chunks[1], "diff --git a/file2.txt") {
+		t.Fatalf("second chunk does not contain file2 header: %s", chunks[1])
+	}
+}
+
+func TestSplitDiffIntoChunks_LargeSingleFile(t *testing.T) {
+	// Create a diff that exceeds maxSize by repeating a line
+	line := "+very long added line that will be repeated many times to exceed the chunk size\n"
+	diff := "diff --git a/large.txt b/large.txt\n" + strings.Repeat(line, 200)
+	max := 500 // small limit
+	chunks := splitDiffIntoChunks([]byte(diff), max)
+	// Ensure no chunk exceeds max size
+	for i, c := range chunks {
+		if len(c) > max {
+			t.Fatalf("chunk %d exceeds max size: %d > %d", i, len(c), max)
+		}
+	}
+	// Recombine chunks and compare to original (ignoring possible split boundaries)
+	recombined := strings.Join(chunks, "")
+	if diff != recombined {
+		if d := cmp.Diff(diff, recombined); d != "" {
+			t.Fatalf("recombined diff differs:\n%s", d)
+		}
+	}
+}