diff --git a/PROJECT.md b/PROJECT.md
index 41591ba..d508809 100644
--- a/PROJECT.md
+++ b/PROJECT.md
@@ -83,7 +83,4 @@ Moon and dwarf planets (Pluto, Ceres, Eris) may be added later.
 - TODO: Implement core `PlanetaryTime` class
 - TODO: Implement conversion from Earth `datetime`
 - TODO: Implement `__str__` / `__repr__`
-- TODO: Write tests for conversion accuracy
-- TODO: Write tests for epoch switching
-- TODO: Populate README with usage examples
 - TODO: Implement `scripts/refresh_data.py` — fetches rotation periods, orbital periods and discovery dates from Wikidata SPARQL endpoint and regenerates hardcoded data in `body.py`, `moon.py` and `epoch.py`; script is not part of the distributed package
diff --git a/README.md b/README.md
index 8da4c84..960e9b5 100644
--- a/README.md
+++ b/README.md
@@ -67,6 +67,8 @@ print(pt.sol)     # 668
 print(pt.hour)    # 14
 print(pt.minute)  # 22
 print(pt.second)  # 7
+print(pt.time)    # "14:22:07"
+print(pt.date)    # "Year 415, Sol 668"
 
 # Mars time since first contact (Viking 1, 1976)
 pt = PlanetaryTime.from_earth(now, Body.MARS, EpochType.CONTACT)
diff --git a/tests/test_planetary_time.py b/tests/test_planetary_time.py
index 663c896..092295b 100644
--- a/tests/test_planetary_time.py
+++ b/tests/test_planetary_time.py
@@ -80,3 +80,91 @@ def test_repr_contains_year_and_sol() -> None:
     assert "PlanetaryTime(" in r
     assert "year=" in r
     assert "sol=" in r
+
+
+# ------------------------------------------------------------------
+# Conversion accuracy
+# ------------------------------------------------------------------
+
+def test_conversion_accuracy_sol_hour_minute() -> None:
+    """26h 30m after epoch on Mars: sol 1, hour 1, minute 30."""
+    epoch_dt = get_epoch_date(Body.MARS, EpochType.DISCOVERY)
+    # Mars sol = 25 h; 26h 30m = 1 sol + 1h 30m
+    pt = PlanetaryTime.from_earth(epoch_dt + timedelta(hours=26, minutes=30), Body.MARS, EpochType.DISCOVERY)
+    assert pt.year == 0
+    assert pt.sol == 1
+    assert pt.hour == 1
+    assert pt.minute == 30
+    assert pt.second == 0
+
+
+def test_conversion_accuracy_seconds() -> None:
+    """45 seconds after epoch: only second counter advances."""
+    epoch_dt = get_epoch_date(Body.MARS, EpochType.DISCOVERY)
+    pt = PlanetaryTime.from_earth(epoch_dt + timedelta(seconds=45), Body.MARS, EpochType.DISCOVERY)
+    assert pt.year == 0
+    assert pt.sol == 0
+    assert pt.hour == 0
+    assert pt.minute == 0
+    assert pt.second == 45
+
+
+def test_conversion_accuracy_year_boundary() -> None:
+    """Exactly one Mars year after epoch lands on year 1, sol 0, 00:00:00."""
+    epoch_dt = get_epoch_date(Body.MARS, EpochType.DISCOVERY)
+    one_year_seconds = Body.MARS.sols_per_year * Body.MARS.hours_per_sol * 3600
+    pt = PlanetaryTime.from_earth(epoch_dt + timedelta(seconds=one_year_seconds), Body.MARS, EpochType.DISCOVERY)
+    assert pt.year == 1
+    assert pt.sol == 0
+    assert pt.hour == 0
+    assert pt.minute == 0
+    assert pt.second == 0
+
+
+# ------------------------------------------------------------------
+# Epoch switching
+# ------------------------------------------------------------------
+
+def test_epoch_switching_discovery_vs_contact_differ() -> None:
+    """Discovery (1610) and contact (1976) epochs give significantly different years."""
+    dt = datetime(2024, 1, 1, tzinfo=timezone.utc)
+    pt_disc = PlanetaryTime.from_earth(dt, Body.MARS, EpochType.DISCOVERY)
+    pt_cont = PlanetaryTime.from_earth(dt, Body.MARS, EpochType.CONTACT)
+    assert pt_disc.year > pt_cont.year
+
+
+def test_epoch_switching_preserves_body_and_epoch_type() -> None:
+    """Switching epoch type is reflected in the epoch_type property; body stays the same."""
+    dt = datetime(2024, 1, 1, tzinfo=timezone.utc)
+    pt_disc = PlanetaryTime.from_earth(dt, Body.MARS, EpochType.DISCOVERY)
+    pt_cont = PlanetaryTime.from_earth(dt, Body.MARS, EpochType.CONTACT)
+    assert pt_disc.body is Body.MARS
+    assert pt_cont.body is Body.MARS
+    assert pt_disc.epoch_type is EpochType.DISCOVERY
+    assert pt_cont.epoch_type is EpochType.CONTACT
+
+
+def test_epoch_switching_contact_sol_count_is_smaller() -> None:
+    """Contact epoch is later, so sol count from contact is smaller than from discovery."""
+    dt = datetime(2024, 1, 1, tzinfo=timezone.utc)
+    pt_disc = PlanetaryTime.from_earth(dt, Body.MARS, EpochType.DISCOVERY)
+    pt_cont = PlanetaryTime.from_earth(dt, Body.MARS, EpochType.CONTACT)
+    total_sols_disc = pt_disc.year * Body.MARS.sols_per_year + pt_disc.sol
+    total_sols_cont = pt_cont.year * Body.MARS.sols_per_year + pt_cont.sol
+    assert total_sols_disc > total_sols_cont
+
+
+# ------------------------------------------------------------------
+# time and date properties
+# ------------------------------------------------------------------
+
+def test_time_property_format() -> None:
+    epoch_dt = get_epoch_date(Body.MARS, EpochType.DISCOVERY)
+    pt = PlanetaryTime.from_earth(epoch_dt + timedelta(hours=3, minutes=7, seconds=9), Body.MARS, EpochType.DISCOVERY)
+    assert pt.time == "03:07:09"
+
+
+def test_date_property_format() -> None:
+    epoch_dt = get_epoch_date(Body.MARS, EpochType.DISCOVERY)
+    pt = PlanetaryTime.from_earth(epoch_dt + timedelta(hours=Body.MARS.hours_per_sol + 1), Body.MARS, EpochType.DISCOVERY)
+    assert pt.date == "Year 0, Sol 1"