test(e2e): add 9 launcher lifecycle tests for Phase 9

Five test the constructor only (seed handling, eager profile build,
fail-fast pin validation) and always run. Four spin up the patched
Firefox and exercise the full `with InvisiblePlaywright(...)` lifecycle,
gated on a locally cached binary so CI without the binary skips
cleanly. All 230 tests pass on Windows with the binary fetched.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/test_e2e.py

@@ -0,0 +1,143 @@
+"""E2E tests for the launcher lifecycle.
+
+Tests requiring the patched Firefox binary are gated behind the
+``firefox_binary`` fixture, which skips the test cleanly when the
+binary is not cached locally and cannot be downloaded (e.g. no
+network or no release token). The constructor-only tests (seed
+handling) do not need a binary and always run.
+"""
+from __future__ import annotations
+
+import sys
+
+import pytest
+
+from invisible_playwright import InvisiblePlaywright
+from invisible_playwright.constants import BINARY_ENTRY_REL
+
+
+@pytest.fixture(scope="session")
+def firefox_binary():
+    """Locate the patched Firefox binary or skip the calling test.
+
+    We do NOT trigger a network download here: ``ensure_binary`` would
+    pull a multi-hundred-megabyte archive from a private release,
+    which is not appropriate inside a unit/E2E test run. Instead we
+    look for an already-cached binary; if missing we skip.
+    """
+    if sys.platform not in BINARY_ENTRY_REL:
+        pytest.skip(f"unsupported platform: {sys.platform}")
+    from invisible_playwright.download import cache_dir_for_version
+    entry = cache_dir_for_version() / BINARY_ENTRY_REL[sys.platform]
+    if not entry.exists():
+        pytest.skip(
+            "patched Firefox binary not cached; run `invisible-playwright fetch` "
+            "to enable E2E tests"
+        )
+    return str(entry)
+
+
+# ────────────────────────────────────────────────────────────────────
+# Constructor-only tests (no browser launch required)
+# ────────────────────────────────────────────────────────────────────
+
+
+@pytest.mark.e2e
+def test_e3_seed_is_accessible():
+    """E3: explicit seed is stored on the instance after construction."""
+    ip = InvisiblePlaywright(seed=42)
+    assert ip.seed == 42
+
+
+@pytest.mark.e2e
+def test_e4_random_seed_when_none():
+    """E4: omitting seed → a fresh positive int31 is chosen."""
+    ip = InvisiblePlaywright()
+    assert isinstance(ip.seed, int)
+    assert ip.seed > 0
+    assert ip.seed < 2**31
+
+
+@pytest.mark.e2e
+def test_e4b_random_seed_varies_across_instances():
+    """E4 extension: two no-seed instances pick different seeds with
+    overwhelming probability. ``secrets.randbits(31)`` collisions are
+    ~1 in 2 billion, so we accept the negligible flake risk."""
+    seeds = {InvisiblePlaywright().seed for _ in range(5)}
+    assert len(seeds) > 1
+
+
+@pytest.mark.e2e
+def test_e6_profile_built_eagerly():
+    """The constructor materializes the Profile up front so seed-driven
+    fields are accessible without launching a browser. Guards against
+    a regression where Profile generation is deferred into ``__enter__``
+    and an invalid pin therefore raises only at launch time.
+    """
+    ip = InvisiblePlaywright(seed=42)
+    assert ip._profile is not None
+    assert ip._profile.seed == 42
+
+
+@pytest.mark.e2e
+def test_e7_invalid_pin_raises_in_constructor():
+    """Invalid pin keys fail fast at construction, not at __enter__."""
+    with pytest.raises(ValueError):
+        InvisiblePlaywright(seed=42, pin={"not_a_real_field": 1})
+
+
+# ────────────────────────────────────────────────────────────────────
+# Lifecycle tests (require Firefox binary)
+# ────────────────────────────────────────────────────────────────────
+
+
+@pytest.mark.e2e
+def test_e1_sync_context_manager_lifecycle(firefox_binary):
+    """E1: ``with InvisiblePlaywright(...) as browser`` yields a real
+    Playwright Browser object that exposes ``new_context``."""
+    with InvisiblePlaywright(seed=42, binary_path=firefox_binary) as browser:
+        assert browser is not None
+        assert hasattr(browser, "new_context")
+        assert callable(browser.new_context)
+
+
+@pytest.mark.e2e
+def test_e2_create_context_and_page(firefox_binary):
+    """E2: a context spawned from the patched browser can create a page."""
+    with InvisiblePlaywright(seed=42, binary_path=firefox_binary) as browser:
+        ctx = browser.new_context()
+        try:
+            page = ctx.new_page()
+            assert page is not None
+            assert hasattr(page, "goto")
+        finally:
+            ctx.close()
+
+
+@pytest.mark.e2e
+def test_e5_teardown_does_not_raise(firefox_binary):
+    """E5: ``__exit__`` cleans up Playwright + virtual display without raising."""
+    ip = InvisiblePlaywright(seed=42, binary_path=firefox_binary)
+    browser = ip.__enter__()
+    try:
+        assert browser is not None
+    finally:
+        ip.__exit__(None, None, None)
+    # second teardown is idempotent
+    ip.__exit__(None, None, None)
+
+
+@pytest.mark.e2e
+def test_e8_new_context_defaults_from_profile(firefox_binary):
+    """new_context() without kwargs should inherit profile-derived
+    viewport/screen. Guards the monkey-patch installed in __enter__."""
+    with InvisiblePlaywright(seed=42, binary_path=firefox_binary) as browser:
+        ctx = browser.new_context()
+        try:
+            page = ctx.new_page()
+            vp = page.viewport_size
+            assert vp is not None
+            assert vp["width"] > 0
+            assert vp["height"] > 0
+        finally:
+            ctx.close()