diff --git a/etc/make_exchange_calendar_test_csv.py b/etc/make_exchange_calendar_test_csv.py
index 53ed7314..bcc5430d 100644
--- a/etc/make_exchange_calendar_test_csv.py
+++ b/etc/make_exchange_calendar_test_csv.py
@@ -70,7 +70,7 @@
 
 df = pd.DataFrame(
     list(zip(cal.opens, cal.closes, cal.break_starts, cal.break_ends)),
-    columns=["market_open", "market_close", "break_start", "break_end"],
+    columns=["open", "close", "break_start", "break_end"],
     index=cal.closes.index,
 )
 
diff --git a/exchange_calendars/exchange_calendar.py b/exchange_calendars/exchange_calendar.py
index 1f54a89b..71a2c244 100644
--- a/exchange_calendars/exchange_calendar.py
+++ b/exchange_calendars/exchange_calendar.py
@@ -370,19 +370,19 @@ def __init__(
             index=_all_days,
             data=collections.OrderedDict(
                 [
-                    ("market_open", self._opens),
+                    ("open", self._opens),
                     ("break_start", break_starts),
                     ("break_end", break_ends),
-                    ("market_close", self._closes),
+                    ("close", self._closes),
                 ]
             ),
             dtype="datetime64[ns, UTC]",
         )
 
-        self.opens_nanos = self.schedule.market_open.values.astype(np.int64)
+        self.opens_nanos = self.schedule.open.values.astype(np.int64)
         self.break_starts_nanos = self.schedule.break_start.values.astype(np.int64)
         self.break_ends_nanos = self.schedule.break_end.values.astype(np.int64)
-        self.closes_nanos = self.schedule.market_close.values.astype(np.int64)
+        self.closes_nanos = self.schedule.close.values.astype(np.int64)
 
         _check_breaks_match(self.break_starts_nanos, self.break_ends_nanos)
 
@@ -749,7 +749,7 @@ def opens(self) -> pd.Series:
             dtype : datetime64[ns, UTC]
                 UTC open time of corresponding session.
         """
-        return self.schedule.market_open
+        return self.schedule.open
 
     @property
     def closes(self) -> pd.Series:
@@ -763,7 +763,7 @@ def closes(self) -> pd.Series:
             dtype : datetime64[ns, UTC]
                 UTC close time of corresponding session.
         """
-        return self.schedule.market_close
+        return self.schedule.close
 
     @property
     def break_starts(self) -> pd.Series:
@@ -955,42 +955,40 @@ def _get_session_idx(self, session: Date, _parse=True) -> int:
             assert isinstance(session_, pd.Timestamp)
         return self.sessions_nanos.searchsorted(session_.value, side="left")
 
-    def session_open(self, session_label: Session, _parse: bool = True) -> pd.Timestamp:
+    def session_open(self, session: Session, _parse: bool = True) -> pd.Timestamp:
         """Return open time for a given session."""
         if _parse:
-            session_label = parse_session(self, session_label, "session_label")
-        return self.schedule.at[session_label, "market_open"]
+            session = parse_session(self, session, "session")
+        return self.schedule.at[session, "open"]
 
-    def session_close(
-        self, session_label: Session, _parse: bool = True
-    ) -> pd.Timestamp:
+    def session_close(self, session: Session, _parse: bool = True) -> pd.Timestamp:
         """Return close time for a given session."""
         if _parse:
-            session_label = parse_session(self, session_label, "session_label")
-        return self.schedule.at[session_label, "market_close"]
+            session = parse_session(self, session, "session")
+        return self.schedule.at[session, "close"]
 
     def session_break_start(
-        self, session_label: Session, _parse: bool = True
+        self, session: Session, _parse: bool = True
     ) -> pd.Timestamp | NaTType:
         """Return break-start time for a given session.
 
         Returns pd.NaT if no break.
         """
         if _parse:
-            session_label = parse_session(self, session_label, "session_label")
-        break_start = self.schedule.at[session_label, "break_start"]
+            session = parse_session(self, session, "session")
+        break_start = self.schedule.at[session, "break_start"]
         return break_start
 
     def session_break_end(
-        self, session_label: Session, _parse: bool = True
+        self, session: Session, _parse: bool = True
     ) -> pd.Timestamp | NaTType:
         """Return break-end time for a given session.
 
         Returns pd.NaT if no break.
         """
         if _parse:
-            session_label = parse_session(self, session_label, "session_label")
-        break_end = self.schedule.at[session_label, "break_end"]
+            session = parse_session(self, session, "session")
+        break_end = self.schedule.at[session, "break_end"]
         return break_end
 
     def session_open_close(
@@ -1215,23 +1213,23 @@ def _date_oob(self, date: pd.Timestamp) -> bool:
             date.value < self.sessions_nanos[0] or date.value > self.sessions_nanos[-1]
         )
 
-    def is_session(self, dt: Date, _parse: bool = True) -> bool:
+    def is_session(self, date: Date, _parse: bool = True) -> bool:
         """Query if a date is a valid session.
 
         Parameters
         ----------
-        dt
+        date
             Date to be queried.
 
         Return
         ------
         bool
-            True if `dt` is a session, False otherwise.
+            True if `date` is a session, False otherwise.
         """
         if _parse:
-            dt = parse_date(dt, "dt", self)
-        idx = self._get_date_idx(dt, _parse=False)
-        return bool(self.sessions_nanos[idx] == dt.value)  # convert from np.bool_
+            date = parse_date(date, "date", self)
+        idx = self._get_date_idx(date, _parse=False)
+        return bool(self.sessions_nanos[idx] == date.value)  # convert from np.bool_
 
     def date_to_session(
         self,
@@ -1355,7 +1353,7 @@ def is_break_minute(self, minute: Minute, _parse: bool = True) -> bool:
         return bool(numpy_bool)
 
     def is_open_on_minute(
-        self, dt: Minute, ignore_breaks: bool = False, _parse: bool = True
+        self, minute: Minute, ignore_breaks: bool = False, _parse: bool = True
     ) -> bool:
         """Query if exchange is open on a given minute.
 
@@ -1365,7 +1363,7 @@ def is_open_on_minute(
 
         Parameters
         ----------
-        dt
+        minute
             Minute being queried.
 
         ignore_breaks
@@ -1376,31 +1374,31 @@ def is_open_on_minute(
         Returns
         -------
         bool
-            Boolean indicting if exchange is open on `dt`.
+            Boolean indicting if exchange is open on `minute`.
 
         See Also
         --------
         is_trading_minute
         """
         if _parse:
-            dt = parse_timestamp(dt, "dt", self)
+            minute = parse_timestamp(minute, "minute", self)
 
-        is_trading_minute = self.is_trading_minute(dt, _parse=False)
+        is_trading_minute = self.is_trading_minute(minute, _parse=False)
         if is_trading_minute or not ignore_breaks:
             return is_trading_minute
         else:
             # not a trading minute although should return True if in break
-            return self.is_break_minute(dt, _parse=False)
+            return self.is_break_minute(minute, _parse=False)
 
-    def next_open(self, dt: Minute, _parse: bool = True) -> pd.Timestamp:
+    def next_open(self, minute: Minute, _parse: bool = True) -> pd.Timestamp:
         """Return next open that follows a given minute.
 
-        If `dt` is a session open, the next session's open will be
+        If `minute` is a session open, the next session's open will be
         returned.
 
         Parameters
         ----------
-        dt
+        minute
             Minute for which to get the next open.
 
         Returns
@@ -1409,29 +1407,29 @@ def next_open(self, dt: Minute, _parse: bool = True) -> pd.Timestamp:
             UTC timestamp of the next open.
         """
         if _parse:
-            dt = parse_timestamp(dt, "dt", self)
+            minute = parse_timestamp(minute, "minute", self)
         try:
-            idx = next_divider_idx(self.opens_nanos, dt.value)
+            idx = next_divider_idx(self.opens_nanos, minute.value)
         except IndexError:
-            if dt >= self.opens[-1]:
+            if minute >= self.opens[-1]:
                 raise ValueError(
-                    "Minute cannot be the last open or later (received `dt`"
-                    f" parsed as '{dt}'.)"
+                    "Minute cannot be the last open or later (received `minute`"
+                    f" parsed as '{minute}'.)"
                 ) from None
             else:
                 raise
 
         return pd.Timestamp(self.opens_nanos[idx], tz=UTC)
 
-    def next_close(self, dt: Minute, _parse: bool = True) -> pd.Timestamp:
+    def next_close(self, minute: Minute, _parse: bool = True) -> pd.Timestamp:
         """Return next close that follows a given minute.
 
-        If `dt` is a session close, the next session's close will be
+        If `minute` is a session close, the next session's close will be
         returned.
 
         Parameters
         ----------
-        dt
+        minute
             Minute for which to get the next close.
 
         Returns
@@ -1440,28 +1438,28 @@ def next_close(self, dt: Minute, _parse: bool = True) -> pd.Timestamp:
             UTC timestamp of the next close.
         """
         if _parse:
-            dt = parse_timestamp(dt, "dt", self)
+            minute = parse_timestamp(minute, "minute", self)
         try:
-            idx = next_divider_idx(self.closes_nanos, dt.value)
+            idx = next_divider_idx(self.closes_nanos, minute.value)
         except IndexError:
-            if dt == self.closes[-1]:
+            if minute == self.closes[-1]:
                 raise ValueError(
-                    "Minute cannot be the last close (received `dt` parsed as"
-                    f" '{dt}'.)"
+                    "Minute cannot be the last close (received `minute` parsed as"
+                    f" '{minute}'.)"
                 ) from None
             else:
                 raise
         return pd.Timestamp(self.closes_nanos[idx], tz=UTC)
 
-    def previous_open(self, dt: Minute, _parse: bool = True) -> pd.Timestamp:
+    def previous_open(self, minute: Minute, _parse: bool = True) -> pd.Timestamp:
         """Return previous open that preceeds a given minute.
 
-        If `dt` is a session open, the previous session's open will be
+        If `minute` is a session open, the previous session's open will be
         returned.
 
         Parameters
         ----------
-        dt
+        minute
             Minute for which to get the previous open.
 
         Returns
@@ -1470,29 +1468,29 @@ def previous_open(self, dt: Minute, _parse: bool = True) -> pd.Timestamp:
             UTC timestamp of the previous open.
         """
         if _parse:
-            dt = parse_timestamp(dt, "dt", self)
+            minute = parse_timestamp(minute, "minute", self)
         try:
-            idx = previous_divider_idx(self.opens_nanos, dt.value)
+            idx = previous_divider_idx(self.opens_nanos, minute.value)
         except ValueError:
-            if dt == self.opens[0]:
+            if minute == self.opens[0]:
                 raise ValueError(
-                    "Minute cannot be the first open (received `dt` parsed as"
-                    f" '{dt}'.)"
+                    "Minute cannot be the first open (received `minute` parsed as"
+                    f" '{minute}'.)"
                 ) from None
             else:
                 raise
 
         return pd.Timestamp(self.opens_nanos[idx], tz=UTC)
 
-    def previous_close(self, dt: Minute, _parse: bool = True) -> pd.Timestamp:
+    def previous_close(self, minute: Minute, _parse: bool = True) -> pd.Timestamp:
         """Return previous close that preceeds a given minute.
 
-        If `dt` is a session close, the previous session's close will be
+        If `minute` is a session close, the previous session's close will be
         returned.
 
         Parameters
         ----------
-        dt
+        minute
             Minute for which to get the previous close.
 
         Returns
@@ -1501,26 +1499,26 @@ def previous_close(self, dt: Minute, _parse: bool = True) -> pd.Timestamp:
             UTC timestamp of the previous close.
         """
         if _parse:
-            dt = parse_timestamp(dt, "dt", self)
+            minute = parse_timestamp(minute, "minute", self)
         try:
-            idx = previous_divider_idx(self.closes_nanos, dt.value)
+            idx = previous_divider_idx(self.closes_nanos, minute.value)
         except ValueError:
-            if dt <= self.closes[0]:
+            if minute <= self.closes[0]:
                 raise ValueError(
                     "Minute cannot be the first close or earlier (received"
-                    f" `dt` parsed as '{dt}'.)"
+                    f" `minute` parsed as '{minute}'.)"
                 ) from None
             else:
                 raise
 
         return pd.Timestamp(self.closes_nanos[idx], tz=UTC)
 
-    def next_minute(self, dt: Minute, _parse: bool = True) -> pd.Timestamp:
+    def next_minute(self, minute: Minute, _parse: bool = True) -> pd.Timestamp:
         """Return trading minute that immediately follows a given minute.
 
         Parameters
         ----------
-        dt
+        minute
             Minute for which to get next trading minute. Minute can be a
             trading or a non-trading minute.
 
@@ -1535,21 +1533,21 @@ def next_minute(self, dt: Minute, _parse: bool = True) -> pd.Timestamp:
             If `minute` is the last calendar minute.
         """
         if _parse:
-            dt = parse_timestamp(dt, "dt", self)
+            minute = parse_timestamp(minute, "minute", self)
         try:
-            idx = next_divider_idx(self.minutes_nanos, dt.value)
+            idx = next_divider_idx(self.minutes_nanos, minute.value)
         except IndexError:
             # dt > last_minute handled via parsing
-            if dt == self.last_minute:
+            if minute == self.last_minute:
                 raise errors.RequestedMinuteOutOfBounds(self, False) from None
         return self.minutes[idx]
 
-    def previous_minute(self, dt: Minute, _parse: bool = True) -> pd.Timestamp:
+    def previous_minute(self, minute: Minute, _parse: bool = True) -> pd.Timestamp:
         """Return trading minute that immediately preceeds a given minute.
 
         Parameters
         ----------
-        dt
+        minute
             Minute for which to get previous trading minute. Minute can be
             a trading or a non-trading minute.
 
@@ -1564,12 +1562,12 @@ def previous_minute(self, dt: Minute, _parse: bool = True) -> pd.Timestamp:
             If `minute` is the first calendar minute.
         """
         if _parse:
-            dt = parse_timestamp(dt, "dt", self)
+            minute = parse_timestamp(minute, "minute", self)
         try:
-            idx = previous_divider_idx(self.minutes_nanos, dt.value)
+            idx = previous_divider_idx(self.minutes_nanos, minute.value)
         except ValueError:
             # dt < first_minute handled via parsing
-            if dt == self.first_minute:
+            if minute == self.first_minute:
                 raise errors.RequestedMinuteOutOfBounds(self, True) from None
         return self.minutes[idx]
 
@@ -2073,24 +2071,24 @@ def _get_sessions_slice(self, start: Date, end: Date, _parse=True) -> slice:
         return slice(slice_start, slice_end)
 
     def sessions_in_range(
-        self, start_session_label: Date, end_session_label: Date, _parse: bool = True
+        self, start: Date, end: Date, _parse: bool = True
     ) -> pd.DatetimeIndex:
         """Return sessions within a given range.
 
         Parameters
         ----------
-        start_session_label
+        start
             Start of session range (range inclusive of `start`).
 
-        end_session_label
+        end
             End of session range (range inclusive of `end`).
 
         Returns
         -------
         pd.DatetimeIndex
-            Sessions from `start_session_label` through `end_session_label`.
+            Sessions from `start` through `end`.
         """
-        slc = self._get_sessions_slice(start_session_label, end_session_label, _parse)
+        slc = self._get_sessions_slice(start, end, _parse)
         return self.sessions[slc]
 
     def sessions_has_break(self, start: Date, end: Date, _parse: bool = True) -> bool:
@@ -2218,7 +2216,7 @@ def sessions_opens(self, start: Date, end: Date, _parse: bool = True) -> pd.Seri
                 UTC open times for corresponding sessions.
         """
         start, end = self._parse_start_end_dates(start, end, _parse)
-        return self.schedule.loc[start:end, "market_open"]
+        return self.schedule.loc[start:end, "open"]
 
     def sessions_closes(self, start: Date, end: Date, _parse: bool = True) -> pd.Series:
         """Return UTC close time by session for sessions in given range.
@@ -2240,7 +2238,7 @@ def sessions_closes(self, start: Date, end: Date, _parse: bool = True) -> pd.Ser
                 UTC close times for corresponding sessions.
         """
         start, end = self._parse_start_end_dates(start, end, _parse)
-        return self.schedule.loc[start:end, "market_close"]
+        return self.schedule.loc[start:end, "close"]
 
     def sessions_minutes_count(
         self, start: Date, end: Date, _parse: bool = True
diff --git a/tests/resources/24-5.csv b/tests/resources/24-5.csv
index c0ca124a..1668f61f 100644
--- a/tests/resources/24-5.csv
+++ b/tests/resources/24-5.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 2018-01-01T00:00:00Z,2018-01-01T00:00:00Z,2018-01-02T00:00:00Z,,
 2018-01-02T00:00:00Z,2018-01-02T00:00:00Z,2018-01-03T00:00:00Z,,
 2018-01-03T00:00:00Z,2018-01-03T00:00:00Z,2018-01-04T00:00:00Z,,
diff --git a/tests/resources/24-7.csv b/tests/resources/24-7.csv
index a6ad42ff..38da8c55 100644
--- a/tests/resources/24-7.csv
+++ b/tests/resources/24-7.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 2016-01-01T00:00:00Z,2016-01-01T00:00:00Z,2016-01-02T00:00:00Z,,
 2016-01-02T00:00:00Z,2016-01-02T00:00:00Z,2016-01-03T00:00:00Z,,
 2016-01-03T00:00:00Z,2016-01-03T00:00:00Z,2016-01-04T00:00:00Z,,
diff --git a/tests/resources/aixk.csv b/tests/resources/aixk.csv
index 35afa5f7..e2c203c5 100644
--- a/tests/resources/aixk.csv
+++ b/tests/resources/aixk.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 2017-01-03T00:00:00Z,2017-01-03T05:00:00Z,2017-01-03T11:00:00Z,,
 2017-01-04T00:00:00Z,2017-01-04T05:00:00Z,2017-01-04T11:00:00Z,,
 2017-01-05T00:00:00Z,2017-01-05T05:00:00Z,2017-01-05T11:00:00Z,,
diff --git a/tests/resources/asex.csv b/tests/resources/asex.csv
index 88eb2cc8..b1c41996 100644
--- a/tests/resources/asex.csv
+++ b/tests/resources/asex.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T15:00:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T15:00:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T15:00:00Z,,
diff --git a/tests/resources/bvmf.csv b/tests/resources/bvmf.csv
index 7dcd1a9b..fea286ef 100644
--- a/tests/resources/bvmf.csv
+++ b/tests/resources/bvmf.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T12:00:00Z,1990-01-02T19:00:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T12:00:00Z,1990-01-03T19:00:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T12:00:00Z,1990-01-04T19:00:00Z,,
diff --git a/tests/resources/cmes.csv b/tests/resources/cmes.csv
index 58682744..6c4e06a1 100644
--- a/tests/resources/cmes.csv
+++ b/tests/resources/cmes.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-01T23:00:00Z,1990-01-02T23:00:00Z,,
 1990-01-03T00:00:00Z,1990-01-02T23:00:00Z,1990-01-03T23:00:00Z,,
 1990-01-04T00:00:00Z,1990-01-03T23:00:00Z,1990-01-04T23:00:00Z,,
diff --git a/tests/resources/iepa.csv b/tests/resources/iepa.csv
index 84d89a2c..ca511791 100644
--- a/tests/resources/iepa.csv
+++ b/tests/resources/iepa.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T01:00:00Z,1990-01-02T23:00:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T01:00:00Z,1990-01-03T23:00:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T01:00:00Z,1990-01-04T23:00:00Z,,
diff --git a/tests/resources/xams.csv b/tests/resources/xams.csv
index c2c8ee21..7ee254d3 100644
--- a/tests/resources/xams.csv
+++ b/tests/resources/xams.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T16:30:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T16:30:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T16:30:00Z,,
diff --git a/tests/resources/xasx.csv b/tests/resources/xasx.csv
index d49fb699..049c2f71 100644
--- a/tests/resources/xasx.csv
+++ b/tests/resources/xasx.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-01T23:00:00Z,1990-01-02T05:00:00Z,,
 1990-01-03T00:00:00Z,1990-01-02T23:00:00Z,1990-01-03T05:00:00Z,,
 1990-01-04T00:00:00Z,1990-01-03T23:00:00Z,1990-01-04T05:00:00Z,,
diff --git a/tests/resources/xbkk.csv b/tests/resources/xbkk.csv
index 0bf71019..94cf3919 100644
--- a/tests/resources/xbkk.csv
+++ b/tests/resources/xbkk.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-03T00:00:00Z,1990-01-03T03:00:00Z,1990-01-03T09:30:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T03:00:00Z,1990-01-04T09:30:00Z,,
 1990-01-05T00:00:00Z,1990-01-05T03:00:00Z,1990-01-05T09:30:00Z,,
diff --git a/tests/resources/xbog.csv b/tests/resources/xbog.csv
index 86842fc7..e58e3f74 100644
--- a/tests/resources/xbog.csv
+++ b/tests/resources/xbog.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T14:30:00Z,1990-01-02T21:00:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T14:30:00Z,1990-01-03T21:00:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T14:30:00Z,1990-01-04T21:00:00Z,,
diff --git a/tests/resources/xbom.csv b/tests/resources/xbom.csv
index b05f4c81..b9cbb550 100644
--- a/tests/resources/xbom.csv
+++ b/tests/resources/xbom.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1997-01-01T00:00:00Z,1997-01-01T03:45:00Z,1997-01-01T10:00:00Z,,
 1997-01-02T00:00:00Z,1997-01-02T03:45:00Z,1997-01-02T10:00:00Z,,
 1997-01-03T00:00:00Z,1997-01-03T03:45:00Z,1997-01-03T10:00:00Z,,
diff --git a/tests/resources/xbru.csv b/tests/resources/xbru.csv
index 62266e10..53cd698b 100644
--- a/tests/resources/xbru.csv
+++ b/tests/resources/xbru.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T16:30:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T16:30:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T16:30:00Z,,
diff --git a/tests/resources/xbse.csv b/tests/resources/xbse.csv
index 7ac154c1..d40aed6a 100644
--- a/tests/resources/xbse.csv
+++ b/tests/resources/xbse.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T15:45:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T15:45:00Z,,
 1990-01-05T00:00:00Z,1990-01-05T08:00:00Z,1990-01-05T15:45:00Z,,
diff --git a/tests/resources/xbud.csv b/tests/resources/xbud.csv
index 1e3dcfc6..2e081ce1 100644
--- a/tests/resources/xbud.csv
+++ b/tests/resources/xbud.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T16:00:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T16:00:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T16:00:00Z,,
diff --git a/tests/resources/xbue.csv b/tests/resources/xbue.csv
index d4aee642..162efee5 100644
--- a/tests/resources/xbue.csv
+++ b/tests/resources/xbue.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T13:00:00Z,1990-01-02T19:00:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T13:00:00Z,1990-01-03T19:00:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T13:00:00Z,1990-01-04T19:00:00Z,,
diff --git a/tests/resources/xcbf.csv b/tests/resources/xcbf.csv
index c9df8f00..7c187a8c 100644
--- a/tests/resources/xcbf.csv
+++ b/tests/resources/xcbf.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T14:30:00Z,1990-01-02T21:15:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T14:30:00Z,1990-01-03T21:15:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T14:30:00Z,1990-01-04T21:15:00Z,,
diff --git a/tests/resources/xcse.csv b/tests/resources/xcse.csv
index c9594839..c09fb1df 100644
--- a/tests/resources/xcse.csv
+++ b/tests/resources/xcse.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T16:00:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T16:00:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T16:00:00Z,,
diff --git a/tests/resources/xdub.csv b/tests/resources/xdub.csv
index 3e2952f5..4c9b31d8 100644
--- a/tests/resources/xdub.csv
+++ b/tests/resources/xdub.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T16:28:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T16:28:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T16:28:00Z,,
diff --git a/tests/resources/xetr.csv b/tests/resources/xetr.csv
index cb5c22ac..5c21a2af 100644
--- a/tests/resources/xetr.csv
+++ b/tests/resources/xetr.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T16:30:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T16:30:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T16:30:00Z,,
diff --git a/tests/resources/xfra.csv b/tests/resources/xfra.csv
index 59702fea..826b07ae 100644
--- a/tests/resources/xfra.csv
+++ b/tests/resources/xfra.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T16:30:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T16:30:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T16:30:00Z,,
diff --git a/tests/resources/xhel.csv b/tests/resources/xhel.csv
index 3ef929b8..5255a2d8 100644
--- a/tests/resources/xhel.csv
+++ b/tests/resources/xhel.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T16:30:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T16:30:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T16:30:00Z,,
diff --git a/tests/resources/xhkg.csv b/tests/resources/xhkg.csv
index ec3dff1f..1c6dfc81 100644
--- a/tests/resources/xhkg.csv
+++ b/tests/resources/xhkg.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T02:00:00Z,1990-01-02T08:00:00Z,1990-01-02T04:00:00Z,1990-01-02T05:00:00Z
 1990-01-03T00:00:00Z,1990-01-03T02:00:00Z,1990-01-03T08:00:00Z,1990-01-03T04:00:00Z,1990-01-03T05:00:00Z
 1990-01-04T00:00:00Z,1990-01-04T02:00:00Z,1990-01-04T08:00:00Z,1990-01-04T04:00:00Z,1990-01-04T05:00:00Z
diff --git a/tests/resources/xice.csv b/tests/resources/xice.csv
index 2ac2a0ed..defadc80 100644
--- a/tests/resources/xice.csv
+++ b/tests/resources/xice.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 2010-01-04T00:00:00Z,2010-01-04T09:30:00Z,2010-01-04T15:30:00Z,,
 2010-01-05T00:00:00Z,2010-01-05T09:30:00Z,2010-01-05T15:30:00Z,,
 2010-01-06T00:00:00Z,2010-01-06T09:30:00Z,2010-01-06T15:30:00Z,,
diff --git a/tests/resources/xidx.csv b/tests/resources/xidx.csv
index ca8ddcb1..0f1d8205 100644
--- a/tests/resources/xidx.csv
+++ b/tests/resources/xidx.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T02:00:00Z,1990-01-02T08:50:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T02:00:00Z,1990-01-03T08:50:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T02:00:00Z,1990-01-04T08:50:00Z,,
diff --git a/tests/resources/xist.csv b/tests/resources/xist.csv
index 90cd7e3b..3086eea6 100644
--- a/tests/resources/xist.csv
+++ b/tests/resources/xist.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T16:00:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T16:00:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T16:00:00Z,,
diff --git a/tests/resources/xjse.csv b/tests/resources/xjse.csv
index 669d17aa..180c8669 100644
--- a/tests/resources/xjse.csv
+++ b/tests/resources/xjse.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T07:00:00Z,1990-01-02T15:00:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T07:00:00Z,1990-01-03T15:00:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T07:00:00Z,1990-01-04T15:00:00Z,,
diff --git a/tests/resources/xkar.csv b/tests/resources/xkar.csv
index 81fb9bc2..724653d5 100644
--- a/tests/resources/xkar.csv
+++ b/tests/resources/xkar.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-01T00:00:00Z,1990-01-01T04:32:00Z,1990-01-01T10:30:00Z,,
 1990-01-02T00:00:00Z,1990-01-02T04:32:00Z,1990-01-02T10:30:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T04:32:00Z,1990-01-03T10:30:00Z,,
diff --git a/tests/resources/xkls.csv b/tests/resources/xkls.csv
index c8583c1a..92514335 100644
--- a/tests/resources/xkls.csv
+++ b/tests/resources/xkls.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T01:00:00Z,1990-01-02T09:00:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T01:00:00Z,1990-01-03T09:00:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T01:00:00Z,1990-01-04T09:00:00Z,,
diff --git a/tests/resources/xkrx.csv b/tests/resources/xkrx.csv
index c3e3d4a0..69a373b6 100644
--- a/tests/resources/xkrx.csv
+++ b/tests/resources/xkrx.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1986-01-04T00:00:00Z,1986-01-04T02:00:00Z,1986-01-04T06:30:00Z,1986-01-04T03:00:00Z,1986-01-04T04:30:00Z
 1986-01-06T00:00:00Z,1986-01-06T01:00:00Z,1986-01-06T06:30:00Z,1986-01-06T03:00:00Z,1986-01-06T04:30:00Z
 1986-01-07T00:00:00Z,1986-01-07T01:00:00Z,1986-01-07T06:30:00Z,1986-01-07T03:00:00Z,1986-01-07T04:30:00Z
diff --git a/tests/resources/xlim.csv b/tests/resources/xlim.csv
index dcd7960e..3a7c7558 100644
--- a/tests/resources/xlim.csv
+++ b/tests/resources/xlim.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T13:00:00Z,1990-01-02T20:00:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T13:00:00Z,1990-01-03T20:00:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T13:00:00Z,1990-01-04T20:00:00Z,,
diff --git a/tests/resources/xlis.csv b/tests/resources/xlis.csv
index d50b9ac7..1d752076 100644
--- a/tests/resources/xlis.csv
+++ b/tests/resources/xlis.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T16:30:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T16:30:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T16:30:00Z,,
diff --git a/tests/resources/xlon.csv b/tests/resources/xlon.csv
index b74ed490..008ecbf0 100644
--- a/tests/resources/xlon.csv
+++ b/tests/resources/xlon.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T16:30:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T16:30:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T16:30:00Z,,
diff --git a/tests/resources/xmad.csv b/tests/resources/xmad.csv
index fd578d94..802dc2e0 100644
--- a/tests/resources/xmad.csv
+++ b/tests/resources/xmad.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T16:30:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T16:30:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T16:30:00Z,,
diff --git a/tests/resources/xmex.csv b/tests/resources/xmex.csv
index 506afccf..7984010c 100644
--- a/tests/resources/xmex.csv
+++ b/tests/resources/xmex.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T14:30:00Z,1990-01-02T21:00:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T14:30:00Z,1990-01-03T21:00:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T14:30:00Z,1990-01-04T21:00:00Z,,
diff --git a/tests/resources/xmil.csv b/tests/resources/xmil.csv
index 7fd26a47..24247484 100644
--- a/tests/resources/xmil.csv
+++ b/tests/resources/xmil.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T16:30:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T16:30:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T16:30:00Z,,
diff --git a/tests/resources/xmos.csv b/tests/resources/xmos.csv
index d171705e..9eeac5b3 100644
--- a/tests/resources/xmos.csv
+++ b/tests/resources/xmos.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-03T00:00:00Z,1990-01-03T07:00:00Z,1990-01-03T15:45:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T07:00:00Z,1990-01-04T15:45:00Z,,
 1990-01-05T00:00:00Z,1990-01-05T07:00:00Z,1990-01-05T15:45:00Z,,
diff --git a/tests/resources/xnys.csv b/tests/resources/xnys.csv
index 9d030bd5..bcebc113 100644
--- a/tests/resources/xnys.csv
+++ b/tests/resources/xnys.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T14:30:00Z,1990-01-02T21:00:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T14:30:00Z,1990-01-03T21:00:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T14:30:00Z,1990-01-04T21:00:00Z,,
diff --git a/tests/resources/xnze.csv b/tests/resources/xnze.csv
index d2216bff..27e271cb 100644
--- a/tests/resources/xnze.csv
+++ b/tests/resources/xnze.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-03T00:00:00Z,1990-01-02T21:00:00Z,1990-01-03T03:45:00Z,,
 1990-01-04T00:00:00Z,1990-01-03T21:00:00Z,1990-01-04T03:45:00Z,,
 1990-01-05T00:00:00Z,1990-01-04T21:00:00Z,1990-01-05T03:45:00Z,,
diff --git a/tests/resources/xosl.csv b/tests/resources/xosl.csv
index ba0d448c..8794c151 100644
--- a/tests/resources/xosl.csv
+++ b/tests/resources/xosl.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T15:20:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T15:20:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T15:20:00Z,,
diff --git a/tests/resources/xpar.csv b/tests/resources/xpar.csv
index ae00d44e..a4c87ff9 100644
--- a/tests/resources/xpar.csv
+++ b/tests/resources/xpar.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T16:30:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T16:30:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T16:30:00Z,,
diff --git a/tests/resources/xphs.csv b/tests/resources/xphs.csv
index 01e06f5e..a6b0f66f 100644
--- a/tests/resources/xphs.csv
+++ b/tests/resources/xphs.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-01T00:00:00Z,1990-01-01T01:30:00Z,1990-01-01T07:30:00Z,,
 1990-01-02T00:00:00Z,1990-01-02T01:30:00Z,1990-01-02T07:30:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T01:30:00Z,1990-01-03T07:30:00Z,,
diff --git a/tests/resources/xpra.csv b/tests/resources/xpra.csv
index 60348a5c..6d343b9b 100644
--- a/tests/resources/xpra.csv
+++ b/tests/resources/xpra.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T15:20:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T15:20:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T15:20:00Z,,
diff --git a/tests/resources/xses.csv b/tests/resources/xses.csv
index 9557b3a7..536afa02 100644
--- a/tests/resources/xses.csv
+++ b/tests/resources/xses.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1986-01-02T00:00:00Z,1986-01-02T01:00:00Z,1986-01-02T09:00:00Z,,
 1986-01-03T00:00:00Z,1986-01-03T01:00:00Z,1986-01-03T09:00:00Z,,
 1986-01-06T00:00:00Z,1986-01-06T01:00:00Z,1986-01-06T09:00:00Z,,
diff --git a/tests/resources/xsgo.csv b/tests/resources/xsgo.csv
index 99bce4b4..05edfb25 100644
--- a/tests/resources/xsgo.csv
+++ b/tests/resources/xsgo.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T12:30:00Z,1990-01-02T20:00:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T12:30:00Z,1990-01-03T20:00:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T12:30:00Z,1990-01-04T20:00:00Z,,
diff --git a/tests/resources/xshg.csv b/tests/resources/xshg.csv
index 02671306..7d89fb45 100644
--- a/tests/resources/xshg.csv
+++ b/tests/resources/xshg.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-12-03T00:00:00Z,1990-12-03T01:30:00Z,1990-12-03T07:00:00Z,1990-12-03T03:30:00Z,1990-12-03T05:00:00Z
 1990-12-04T00:00:00Z,1990-12-04T01:30:00Z,1990-12-04T07:00:00Z,1990-12-04T03:30:00Z,1990-12-04T05:00:00Z
 1990-12-05T00:00:00Z,1990-12-05T01:30:00Z,1990-12-05T07:00:00Z,1990-12-05T03:30:00Z,1990-12-05T05:00:00Z
diff --git a/tests/resources/xsto.csv b/tests/resources/xsto.csv
index 2a379dd6..4b4bc7a2 100644
--- a/tests/resources/xsto.csv
+++ b/tests/resources/xsto.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T16:30:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T16:30:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T16:30:00Z,,
diff --git a/tests/resources/xswx.csv b/tests/resources/xswx.csv
index 84b1bc57..827bdeb1 100644
--- a/tests/resources/xswx.csv
+++ b/tests/resources/xswx.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T16:30:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T16:30:00Z,,
 1990-01-05T00:00:00Z,1990-01-05T08:00:00Z,1990-01-05T16:30:00Z,,
diff --git a/tests/resources/xtae.csv b/tests/resources/xtae.csv
index 986cc596..bb3a272a 100644
--- a/tests/resources/xtae.csv
+++ b/tests/resources/xtae.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 2019-01-01T00:00:00Z,2019-01-01T08:00:00Z,2019-01-01T15:15:00Z,,
 2019-01-02T00:00:00Z,2019-01-02T08:00:00Z,2019-01-02T15:15:00Z,,
 2019-01-03T00:00:00Z,2019-01-03T08:00:00Z,2019-01-03T15:15:00Z,,
diff --git a/tests/resources/xtai.csv b/tests/resources/xtai.csv
index d80b997b..91094793 100644
--- a/tests/resources/xtai.csv
+++ b/tests/resources/xtai.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T01:00:00Z,1990-01-02T05:30:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T01:00:00Z,1990-01-03T05:30:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T01:00:00Z,1990-01-04T05:30:00Z,,
diff --git a/tests/resources/xtks.csv b/tests/resources/xtks.csv
index 932a6f97..60fc3a9e 100644
--- a/tests/resources/xtks.csv
+++ b/tests/resources/xtks.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 2000-01-04T00:00:00Z,2000-01-04T00:00:00Z,2000-01-04T06:00:00Z,2000-01-04T02:30:00Z,2000-01-04T03:30:00Z
 2000-01-05T00:00:00Z,2000-01-05T00:00:00Z,2000-01-05T06:00:00Z,2000-01-05T02:30:00Z,2000-01-05T03:30:00Z
 2000-01-06T00:00:00Z,2000-01-06T00:00:00Z,2000-01-06T06:00:00Z,2000-01-06T02:30:00Z,2000-01-06T03:30:00Z
diff --git a/tests/resources/xtse.csv b/tests/resources/xtse.csv
index 9d048ab8..a3af4a21 100644
--- a/tests/resources/xtse.csv
+++ b/tests/resources/xtse.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T14:30:00Z,1990-01-02T21:00:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T14:30:00Z,1990-01-03T21:00:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T14:30:00Z,1990-01-04T21:00:00Z,,
diff --git a/tests/resources/xwar.csv b/tests/resources/xwar.csv
index 96626d20..cc0e3d24 100644
--- a/tests/resources/xwar.csv
+++ b/tests/resources/xwar.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T16:00:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T16:00:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T16:00:00Z,,
diff --git a/tests/resources/xwbo.csv b/tests/resources/xwbo.csv
index b8c40c06..1e843357 100644
--- a/tests/resources/xwbo.csv
+++ b/tests/resources/xwbo.csv
@@ -1,4 +1,4 @@
-,market_open,market_close,break_start,break_end
+,open,close,break_start,break_end
 1990-01-02T00:00:00Z,1990-01-02T08:00:00Z,1990-01-02T16:30:00Z,,
 1990-01-03T00:00:00Z,1990-01-03T08:00:00Z,1990-01-03T16:30:00Z,,
 1990-01-04T00:00:00Z,1990-01-04T08:00:00Z,1990-01-04T16:30:00Z,,
diff --git a/tests/test_exchange_calendar.py b/tests/test_exchange_calendar.py
index 9315c716..dcefe3f3 100644
--- a/tests/test_exchange_calendar.py
+++ b/tests/test_exchange_calendar.py
@@ -251,12 +251,12 @@ def sessions(self) -> pd.DatetimeIndex:
     @property
     def opens(self) -> pd.Series:
         """Market open time for each session."""
-        return self.answers.market_open
+        return self.answers.open
 
     @property
     def closes(self) -> pd.Series:
         """Market close time for each session."""
-        return self.answers.market_close
+        return self.answers.close
 
     @property
     def break_starts(self) -> pd.Series:
@@ -1977,7 +1977,7 @@ def name(self, calendar_cls) -> abc.Iterator[str]:
     @pytest.fixture(scope="class")
     def has_24h_session(self, name) -> abc.Iterator[bool]:
         df = get_csv(name)
-        yield (df.market_close == df.market_open.shift(-1)).any()
+        yield (df.close == df.open.shift(-1)).any()
 
     @pytest.fixture(scope="class")
     def default_side(self, has_24h_session) -> abc.Iterator[str]:
@@ -2323,7 +2323,7 @@ def test_daylight_savings(self, default_calendar, daylight_savings_dates):
             next_day = cal.date_to_session(T(date), "next")
             open_date = next_day + pd.Timedelta(days=cal.open_offset)
 
-            the_open = cal.schedule.loc[next_day].market_open
+            the_open = cal.schedule.loc[next_day].open
 
             localized_open = the_open.tz_convert(cal.tz)