diff --git a/tests/conftest.py b/tests/conftest.py
index 22c1251..689297c 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -45,3 +45,9 @@ def legacy_experimental_scn() -> Path:
     if not p.exists():
         pytest.skip("glyr_experimental.scn not found.")
     return p
+
+
+@pytest.fixture()
+def examples_dir() -> Path:
+    """Directory holding the example SCN records."""
+    return EXAMPLES_SCN
diff --git a/tests/test_golden.py b/tests/test_golden.py
new file mode 100644
index 0000000..61ce4c2
--- /dev/null
+++ b/tests/test_golden.py
@@ -0,0 +1,250 @@
+"""Golden values for the record layer.
+
+Every package in the DCPROGS stack reads its records through this code, so a
+change here reaches SCALCS, EKDIST and HJCFIT at once. These are the numbers
+that pin it: fixed outputs for the shipped example records at several
+resolutions and critical times.
+
+Two kinds of assertion, deliberately mixed.
+
+The *golden* ones are exact and will move if any of the arithmetic changes --
+resolution imposition, period grouping, the burst convention, the binning.
+That is what they are for. When one moves, the question to answer is whether
+the change was intended, not whether the number should be updated.
+
+The *invariant* ones hold for any record at any resolution and say what the
+layer guarantees rather than what it happened to produce. They are the ones
+that keep meaning something if the example files are ever replaced.
+
+Resolutions are chosen so the dead time actually bites. The simulated record's
+shortest interval is 125 us, so anything at or below 100 us merges nothing and
+would exercise the concatenation logic not at all.
+"""
+
+from dataclasses import dataclass
+
+import numpy as np
+import pytest
+
+from dcio.analysis import bursts_from_record, from_scn, log_bin_histogram
+from dcio.formats.scn import FLAG_UNUSABLE, read
+
+
+@dataclass(frozen=True)
+class Case:
+    filename: str
+    tres: float
+    tcrit: float
+    n_resolved: int
+    n_open: int
+    n_shut: int
+    n_bursts: int
+    n_openings: int
+    mean_burst_ms: float
+    mean_popen: float
+    open_nbdec: int
+    open_bins: int
+    shut_nbdec: int
+    shut_bins: int
+
+    def __str__(self):
+        return f"{self.filename.split('_')[1][:4]}-{self.tres * 1e6:.0f}us-{self.tcrit * 1e3:.0f}ms"
+
+
+CASES = [
+    Case("glyr_experimental.scn", 2.5e-05, 0.004,
+         n_resolved=3232, n_open=731, n_shut=730,
+         n_bursts=63, n_openings=731,
+         mean_burst_ms=98.629089, mean_popen=0.991578,
+         open_nbdec=8, open_bins=29, shut_nbdec=8, shut_bins=53),
+    Case("glyr_experimental.scn", 0.0001, 0.004,
+         n_resolved=2408, n_open=90, n_shut=89,
+         n_bursts=62, n_openings=90,
+         mean_burst_ms=100.030402, mean_popen=0.997952,
+         open_nbdec=5, open_bins=20, shut_nbdec=5, shut_bins=30),
+    Case("glyr_experimental.scn", 0.0005, 0.01,
+         n_resolved=1812, n_open=67, n_shut=66,
+         n_bursts=56, n_openings=67,
+         mean_burst_ms=111.190894, mean_popen=0.995910,
+         open_nbdec=5, open_bins=17, shut_nbdec=5, shut_bins=27),
+    Case("glyr_simulated.scn", 0.0005, 0.004,
+         n_resolved=33377, n_open=16688, n_shut=16687,
+         n_bursts=9270, n_openings=16688,
+         mean_burst_ms=111.686132, mean_popen=0.993102,
+         open_nbdec=12, open_bins=40, shut_nbdec=12, shut_bins=52),
+    Case("glyr_simulated.scn", 0.001, 0.01,
+         n_resolved=23095, n_open=11547, n_shut=11546,
+         n_bursts=7021, n_openings=11547,
+         mean_burst_ms=149.705263, mean_popen=0.983202,
+         open_nbdec=12, open_bins=37, shut_nbdec=12, shut_bins=49),
+]
+
+
+@pytest.fixture(params=CASES, ids=str)
+def case(request, examples_dir):
+    c = request.param
+    path = examples_dir / c.filename
+    if not path.is_file():
+        pytest.skip(f"{c.filename} not found")
+    return c, from_scn(read(path), tres=c.tres)
+
+
+# --------------------------------------------------------------------------
+# Golden: exact outputs
+# --------------------------------------------------------------------------
+
+class TestGoldenValues:
+
+    def test_resolved_interval_count(self, case):
+        c, rec = case
+        assert rec.n_resolved == c.n_resolved
+
+    def test_period_counts(self, case):
+        c, rec = case
+        assert (rec.periods.n_open, rec.periods.n_shut) == (c.n_open, c.n_shut)
+
+    def test_burst_count_and_openings(self, case):
+        c, rec = case
+        lengths, nops = bursts_from_record(rec, tcrit=c.tcrit)
+        assert len(lengths) == c.n_bursts
+        assert int(nops.sum()) == c.n_openings
+
+    def test_mean_burst_length(self, case):
+        c, rec = case
+        lengths, _ = bursts_from_record(rec, tcrit=c.tcrit)
+        assert lengths.mean() * 1e3 == pytest.approx(c.mean_burst_ms, abs=1e-6)
+
+    def test_mean_popen_within_bursts(self, case):
+        c, rec = case
+        segs = bursts_from_record(rec, tcrit=c.tcrit, intervals_only=True)
+        popen = np.mean([s[0::2].sum() / s.sum() for s in segs])
+        assert popen == pytest.approx(c.mean_popen, abs=1e-6)
+
+    def test_histogram_binning(self, case):
+        c, rec = case
+        for kind, X, nbdec, nbins in (
+            ("open", rec.periods.open_intervals, c.open_nbdec, c.open_bins),
+            ("shut", rec.periods.shut_intervals, c.shut_nbdec, c.shut_bins),
+        ):
+            counts, _, got = log_bin_histogram(X, c.tres)
+            assert got == nbdec, kind
+            assert len(counts) == nbins, kind
+
+
+# --------------------------------------------------------------------------
+# Invariant: what the layer guarantees, for any record at any resolution
+# --------------------------------------------------------------------------
+
+class TestInvariants:
+
+    def test_resolution_actually_bites(self, case):
+        """A golden case that merges nothing tests the concatenation logic not
+        at all. The simulated record's shortest interval is 125 us, so this
+        would silently pass for every tres below that."""
+        c, rec = case
+        assert rec.n_resolved < len(rec.intervals)
+
+    def test_resolved_intervals_are_resolvable_unless_flagged(self, case):
+        """Every resolved interval is at least one dead time long, unless it is
+        flagged unusable.
+
+        Two kinds of exception exist and both are deliberate: a negative
+        sentinel for an unfinished final opening, and the short shut that
+        impose_resolution emits when the last interval of the record is a brief
+        shutting that terminates an open run. Both carry FLAG_UNUSABLE, so the
+        invariant is about the usable intervals -- which is what a consumer
+        actually relies on."""
+        c, rec = case
+        usable = (rec.resolved_flags & FLAG_UNUSABLE) == 0
+        finite = rec.resolved_intervals[usable & (rec.resolved_intervals > 0)]
+        assert (finite >= c.tres - 1e-15).all()
+
+    def test_total_time_is_conserved_after_the_first_resolvable_interval(self, case):
+        """Concatenation moves time between intervals; it must not create or
+        destroy any.
+
+        The head of the record is the one legitimate loss. impose_resolution
+        starts at the first interval that is both resolvable and usable, since
+        anything earlier has a start that cannot be located, and the time
+        before it is dropped. On the experimental example at 100 us that is
+        75.8 us of a 102.7 s record -- small, but not rounding, and an
+        invariant that ignored it would be false rather than approximate."""
+        c, rec = case
+        flags = rec.flags.astype(np.int32).copy()
+        flags[rec.intervals < 0] |= FLAG_UNUSABLE
+        resolvable = np.where((rec.intervals > c.tres) & (flags < FLAG_UNUSABLE))[0]
+        head = rec.intervals[:int(resolvable[0])]
+        discarded = head[head > 0].sum()
+
+        raw = rec.intervals[rec.intervals > 0].sum()
+        resolved = rec.resolved_intervals[rec.resolved_intervals > 0].sum()
+        assert resolved + discarded == pytest.approx(raw, rel=1e-12)
+
+    def test_periods_strictly_alternate(self, case):
+        """set_periods merges runs of the same conductance, so the period list
+        alternates open/shut with no two of a kind adjacent. Burst
+        segmentation depends on this."""
+        c, rec = case
+        is_open = rec.periods.amplitudes != 0.0
+        assert not (is_open[:-1] & is_open[1:]).any()
+        assert not (~is_open[:-1] & ~is_open[1:]).any()
+
+    def test_periods_start_and_end_open(self, case):
+        c, rec = case
+        assert rec.periods.n_open == rec.periods.n_shut + 1
+
+    def test_every_burst_has_an_odd_interval_count(self, case):
+        """Each burst starts and ends on an opening. The missed-events
+        likelihood is a product of matrices alternating A->F and F->A; an
+        even-length burst would end on a shut."""
+        c, rec = case
+        for seq in bursts_from_record(rec, tcrit=c.tcrit, intervals_only=True):
+            assert len(seq) % 2 == 1
+
+    def test_burst_openings_equal_period_openings(self, case):
+        """Every open period belongs to exactly one burst, because the record
+        begins and ends on an opening and nothing between is discarded."""
+        c, rec = case
+        _, nops = bursts_from_record(rec, tcrit=c.tcrit)
+        assert int(nops.sum()) == rec.periods.n_open
+
+    def test_no_burst_contains_a_gap_longer_than_tcrit(self, case):
+        c, rec = case
+        for seq in bursts_from_record(rec, tcrit=c.tcrit, intervals_only=True):
+            if len(seq) > 1:
+                assert (seq[1::2] <= c.tcrit).all()
+
+    def test_histogram_counts_every_interval(self, case):
+        c, rec = case
+        for X in (rec.periods.open_intervals, rec.periods.shut_intervals):
+            counts, edges, _ = log_bin_histogram(X, c.tres)
+            assert counts.sum() == len(X)
+            assert X.max() <= edges[-1]
+
+    def test_tcrit_sign_is_ignored(self, case):
+        c, rec = case
+        pos, _ = bursts_from_record(rec, tcrit=c.tcrit)
+        neg, _ = bursts_from_record(rec, tcrit=-c.tcrit)
+        np.testing.assert_allclose(pos, neg)
+
+
+class TestGoldenTableItself:
+    """The table is only worth having if it covers what it claims to."""
+
+    def test_both_example_records_are_covered(self):
+        assert {c.filename for c in CASES} == {
+            "glyr_experimental.scn", "glyr_simulated.scn"}
+
+    def test_experimental_record_carries_unusable_intervals(self, examples_dir):
+        """The experimental record is the one that exercises flag handling;
+        if it ever stops containing unusable intervals, the burst convention
+        for them is no longer covered by any golden case."""
+        path = examples_dir / "glyr_experimental.scn"
+        if not path.is_file():
+            pytest.skip("glyr_experimental.scn not found")
+        rec = read(path)
+        assert int((rec.flags & FLAG_UNUSABLE != 0).sum()) > 0
+
+    def test_cases_span_more_than_one_resolution_per_record(self):
+        for name in {c.filename for c in CASES}:
+            assert len({c.tres for c in CASES if c.filename == name}) > 1