diff --git a/src/validation/golden_corpus.py b/src/validation/golden_corpus.py
index 998c442..34f2295 100644
--- a/src/validation/golden_corpus.py
+++ b/src/validation/golden_corpus.py
@@ -51,6 +51,21 @@ def corpus_records() -> dict[str, list[dict[str, object]]]:
     }
 
 
+def canonical_content_hash(content: str | bytes) -> str:
+    """Compute the SHA-256 hash of a UTF-8 string with normalized LF line endings.
+
+    Newline Rule: All occurrences of CRLF (\\r\\n) are replaced with LF (\\n).
+    Encoding: UTF-8.
+    Invalid UTF-8: Input bytes that are not valid UTF-8 will raise a UnicodeDecodeError.
+    """
+    if isinstance(content, bytes):
+        text = content.decode("utf-8")
+    else:
+        text = content
+    normalized = text.replace("\r\n", "\n")
+    return hashlib.sha256(normalized.encode("utf-8")).hexdigest()
+
+
 def write_golden_corpus(root: Path = GOLDEN_ROOT) -> dict[str, str]:
     root.mkdir(parents=True, exist_ok=True)
     hashes: dict[str, str] = {}
@@ -58,10 +73,12 @@ def write_golden_corpus(root: Path = GOLDEN_ROOT) -> dict[str, str]:
         path = root / filename
         lines = [json.dumps(record, sort_keys=True, separators=(",", ":"), ensure_ascii=False) for record in records]
         content = "\n".join(lines) + "\n"
-        if path.exists() and path.read_text(encoding="utf-8") != content:
-            raise RuntimeError(f"golden corpus mutation detected: {path}")
-        path.write_text(content, encoding="utf-8")
-        hashes[filename] = hashlib.sha256(content.encode()).hexdigest()
+        if path.exists():
+            existing = path.read_text(encoding="utf-8").replace("\r\n", "\n")
+            if existing != content:
+                raise RuntimeError(f"golden corpus mutation detected: {path}")
+        path.write_text(content, encoding="utf-8", newline="\n")
+        hashes[filename] = canonical_content_hash(content)
     return hashes
 
 
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..41b859d
--- /dev/null
+++ b/tests/__init__.py
@@ -0,0 +1 @@
+"""Test package for CompTextv7."""
diff --git a/tests/test_compression_signals_ts.py b/tests/test_compression_signals_ts.py
index 7c9a1b3..70c8a5f 100644
--- a/tests/test_compression_signals_ts.py
+++ b/tests/test_compression_signals_ts.py
@@ -3,9 +3,11 @@
 import textwrap
 from pathlib import Path
 
+from tests.utils import resolve_tsc_executable
+
 REPO_ROOT = Path(__file__).resolve().parents[1]
 DASHBOARD_APP = REPO_ROOT / "dashboard" / "app"
-TSC = DASHBOARD_APP / "node_modules" / ".bin" / "tsc"
+TSC = resolve_tsc_executable()
 
 
 def run_compression_script(tmp_path: Path, script: str):
diff --git a/tests/test_core_foundation_ts.py b/tests/test_core_foundation_ts.py
index dc53c9f..6b605c6 100644
--- a/tests/test_core_foundation_ts.py
+++ b/tests/test_core_foundation_ts.py
@@ -3,9 +3,11 @@
 import textwrap
 from pathlib import Path
 
+from tests.utils import resolve_tsc_executable
+
 REPO_ROOT = Path(__file__).resolve().parents[1]
 DASHBOARD_APP = REPO_ROOT / "dashboard" / "app"
-TSC = DASHBOARD_APP / "node_modules" / ".bin" / "tsc"
+TSC = resolve_tsc_executable()
 
 
 def run_foundation_script(tmp_path: Path, script: str):
diff --git a/tests/test_golden_corpus_canonical.py b/tests/test_golden_corpus_canonical.py
new file mode 100644
index 0000000..1d02809
--- /dev/null
+++ b/tests/test_golden_corpus_canonical.py
@@ -0,0 +1,40 @@
+from __future__ import annotations
+
+import pytest
+from src.validation.golden_corpus import canonical_content_hash
+
+def test_canonical_content_hash_line_endings() -> None:
+    # 1. LF line endings
+    content_lf = "line1\nline2\nline3\n"
+    hash_lf = canonical_content_hash(content_lf)
+
+    # 2. CRLF line endings
+    content_crlf = "line1\r\nline2\r\nline3\r\n"
+    hash_crlf = canonical_content_hash(content_crlf)
+
+    # 3. Mixed line endings
+    content_mixed = "line1\r\nline2\nline3\r\n"
+    hash_mixed = canonical_content_hash(content_mixed)
+
+    # All three must yield the identical hash
+    assert hash_lf == hash_crlf
+    assert hash_lf == hash_mixed
+
+def test_canonical_content_hash_detects_mutations() -> None:
+    # Ensure byte changes other than line endings are detected
+    content_orig = "line1\nline2\nline3\n"
+    content_mutated = "line1\nline2_altered\nline3\n"
+
+    assert canonical_content_hash(content_orig) != canonical_content_hash(content_mutated)
+
+def test_canonical_content_hash_bytes_support() -> None:
+    content_str = "line1\nline2\r\n"
+    content_bytes = b"line1\nline2\r\n"
+
+    assert canonical_content_hash(content_str) == canonical_content_hash(content_bytes)
+
+def test_canonical_content_hash_invalid_utf8_raises_error() -> None:
+    # Invalid UTF-8 bytes (e.g. 0xff) must raise a UnicodeDecodeError
+    invalid_bytes = b"line1\n\xff\n"
+    with pytest.raises(UnicodeDecodeError):
+        canonical_content_hash(invalid_bytes)
diff --git a/tests/test_reference_index_event_fingerprints_ts.py b/tests/test_reference_index_event_fingerprints_ts.py
index 5578b37..d9b8a30 100644
--- a/tests/test_reference_index_event_fingerprints_ts.py
+++ b/tests/test_reference_index_event_fingerprints_ts.py
@@ -3,9 +3,11 @@
 import textwrap
 from pathlib import Path
 
+from tests.utils import resolve_tsc_executable
+
 REPO_ROOT = Path(__file__).resolve().parents[1]
 DASHBOARD_APP = REPO_ROOT / "dashboard" / "app"
-TSC = DASHBOARD_APP / "node_modules" / ".bin" / "tsc"
+TSC = resolve_tsc_executable()
 
 def run_foundation_script(tmp_path: Path, script: str):
     out_dir = tmp_path / "compiled"
diff --git a/tests/test_replay_artifact_writer_ts.py b/tests/test_replay_artifact_writer_ts.py
index 8256201..c4ae777 100644
--- a/tests/test_replay_artifact_writer_ts.py
+++ b/tests/test_replay_artifact_writer_ts.py
@@ -3,9 +3,11 @@
 import textwrap
 from pathlib import Path
 
+from tests.utils import resolve_tsc_executable
+
 REPO_ROOT = Path(__file__).resolve().parents[1]
 DASHBOARD_APP = REPO_ROOT / "dashboard" / "app"
-TSC = DASHBOARD_APP / "node_modules" / ".bin" / "tsc"
+TSC = resolve_tsc_executable()
 
 def run_foundation_script(tmp_path: Path, script: str):
     out_dir = tmp_path / "compiled"
diff --git a/tests/test_shared_stable_hashing_ts.py b/tests/test_shared_stable_hashing_ts.py
index 66adc6c..0eca726 100644
--- a/tests/test_shared_stable_hashing_ts.py
+++ b/tests/test_shared_stable_hashing_ts.py
@@ -3,9 +3,11 @@
 import textwrap
 from pathlib import Path
 
+from tests.utils import resolve_tsc_executable
+
 REPO_ROOT = Path(__file__).resolve().parents[1]
 DASHBOARD_APP = REPO_ROOT / "dashboard" / "app"
-TSC = DASHBOARD_APP / "node_modules" / ".bin" / "tsc"
+TSC = resolve_tsc_executable()
 
 
 def run_foundation_script(tmp_path: Path, script: str):
diff --git a/tests/test_validation_hardening.py b/tests/test_validation_hardening.py
index 9f0cabc..bfe8726 100644
--- a/tests/test_validation_hardening.py
+++ b/tests/test_validation_hardening.py
@@ -9,7 +9,9 @@
 from src.validation.token_telemetry import SUPPORTED_ENCODINGS, count_tokens, drift_fingerprint
 
 
-def test_golden_corpus_hashes_are_stable() -> None:
+from src.validation.golden_corpus import canonical_content_hash
+
+def test_golden_corpus_canonical_content_hashes_are_stable() -> None:
     hashes = write_golden_corpus()
 
     assert set(hashes) == {
@@ -19,8 +21,8 @@ def test_golden_corpus_hashes_are_stable() -> None:
         "mixed_incident_reference.jsonl",
     }
     for filename, digest in hashes.items():
-        content = Path("datasets/golden", filename).read_bytes()
-        assert hashlib.sha256(content).hexdigest() == digest
+        content_bytes = Path("datasets/golden", filename).read_bytes()
+        assert canonical_content_hash(content_bytes) == digest
 
 
 def test_token_telemetry_supports_required_encodings_deterministically() -> None:
diff --git a/tests/utils/__init__.py b/tests/utils/__init__.py
index e69de29..a243166 100644
--- a/tests/utils/__init__.py
+++ b/tests/utils/__init__.py
@@ -0,0 +1,27 @@
+import os
+import shutil
+from pathlib import Path
+
+def resolve_tsc_executable() -> Path:
+    """Resolve the path to the TypeScript compiler (tsc).
+
+    Prefers the local Node dependency in the dashboard application,
+    falling back to system PATH. Raises FileNotFoundError if missing.
+    """
+    repo_root = Path(__file__).resolve().parents[2]
+    dashboard_app = repo_root / "dashboard" / "app"
+
+    tsc_bin = "tsc.cmd" if os.name == "nt" else "tsc"
+    local_tsc = dashboard_app / "node_modules" / ".bin" / tsc_bin
+
+    if local_tsc.exists():
+        return local_tsc
+
+    system_tsc = shutil.which(tsc_bin)
+    if system_tsc:
+        return Path(system_tsc)
+
+    raise FileNotFoundError(
+        "TypeScript compiler (tsc) not found. Please run 'npm install' "
+        "in dashboard/app or install TypeScript globally."
+    )