Move parsing logic of SampleWindowType to SampleWindow

core/dbt/cli/option_types.py

@@ -1,11 +1,8 @@
-from datetime import datetime
+from typing import Optional
 
-import pytz
-from click import Choice, ParamType
+from click import Choice, Context, Parameter, ParamType
 
-from dbt.artifacts.resources.types import BatchSize
 from dbt.config.utils import normalize_warn_error_options, parse_cli_yaml_string
-from dbt.event_time.event_time import offset_timestamp
 from dbt.event_time.sample_window import SampleWindow
 from dbt.events import ALL_EVENT_NAMES
 from dbt.exceptions import OptionNotYamlDictError, ValidationError
@@ -99,43 +96,16 @@ def convert(self, value, param, ctx):
 class SampleWindowType(ParamType):
     name = "SAMPLE_WINDOW"
 
-    def convert(self, value, param, ctx):
+    def convert(
+        self, value, param: Optional[Parameter], ctx: Optional[Context]
+    ) -> Optional[SampleWindow]:
         if value is None:
-            return
+            return None
 
         if isinstance(value, str):
-            end = datetime.now(tz=pytz.UTC)
-
-            relative_window = value.split(" ")
-            if len(relative_window) != 2:
-                self.fail(
-                    f"Cannot load SAMPLE_WINDOW from '{value}'. Must be of form 'DAYS_INT GRAIN_SIZE'.",
-                    param,
-                    ctx,
-                )
-
-            try:
-                lookback = int(relative_window[0])
-            except Exception:
-                raise self.fail(
-                    f"Unable to convert '{relative_window[0]}' to an integer", param, ctx
-                )
-
             try:
-                batch_size_string = relative_window[1].lower().rstrip("s")
-                batch_size = BatchSize[batch_size_string]
-            except Exception:
-                grains = [size.value for size in BatchSize]
-                grain_plurals = [BatchSize.plural(size) for size in BatchSize]
-                valid_grains = grains + grain_plurals
-                self.fail(
-                    f"Invalid grain size '{relative_window[1]}'. Must be one of {valid_grains}",
-                    param,
-                    ctx,
-                )
-
-            start = offset_timestamp(timestamp=end, batch_size=batch_size, offset=-1 * lookback)
-
-            return SampleWindow(start=start, end=end)
+                return SampleWindow.from_relative_string(value)
+            except Exception as e:
+                self.fail(e.__str__(), param, ctx)
         else:
             self.fail(f"Cannot load SAMPLE_WINDOW from type {type(value)}", param, ctx)

core/dbt/event_time/sample_window.py

@@ -1,8 +1,14 @@
+from __future__ import annotations
+
 from datetime import datetime
 
+import pytz
 from attr import dataclass
 
+from dbt.artifacts.resources.types import BatchSize
+from dbt.event_time.event_time import offset_timestamp
 from dbt_common.dataclass_schema import dbtClassMixin
+from dbt_common.exceptions import DbtRuntimeError
 
 
 @dataclass
@@ -22,3 +28,33 @@ def __post_serialize__(self, data, context):
         new_data["start"] = self.start
         new_data["end"] = self.end
         return new_data
+
+    @classmethod
+    def from_relative_string(cls, relative_string: str) -> SampleWindow:
+        end = datetime.now(tz=pytz.UTC)
+
+        relative_window = relative_string.split(" ")
+        if len(relative_window) != 2:
+            raise DbtRuntimeError(
+                f"Cannot load SAMPLE_WINDOW from '{relative_string}'. Must be of form 'DAYS_INT GRAIN_SIZE'."
+            )
+
+        try:
+            lookback = int(relative_window[0])
+        except Exception:
+            raise DbtRuntimeError(f"Unable to convert '{relative_window[0]}' to an integer.")
+
+        try:
+            batch_size_string = relative_window[1].lower().rstrip("s")
+            batch_size = BatchSize[batch_size_string]
+        except Exception:
+            grains = [size.value for size in BatchSize]
+            grain_plurals = [BatchSize.plural(size) for size in BatchSize]
+            valid_grains = grains + grain_plurals
+            raise DbtRuntimeError(
+                f"Invalid grain size '{relative_window[1]}'. Must be one of {valid_grains}."
+            )
+
+        start = offset_timestamp(timestamp=end, batch_size=batch_size, offset=-1 * lookback)
+
+        return cls(start=start, end=end)

tests/unit/event_time/test_sample_mode.py

@@ -0,0 +1,163 @@
+from datetime import datetime
+from typing import Union
+
+import freezegun
+import pytest
+import pytz
+
+from dbt.event_time.sample_window import SampleWindow
+from dbt_common.exceptions import DbtRuntimeError
+
+
+@pytest.mark.parametrize(
+    "relative_string,expected_result",
+    [
+        (
+            "4 years",
+            SampleWindow(
+                start=datetime(2021, 1, 28, 18, 4, 0, 0, pytz.UTC),
+                end=datetime(2025, 1, 28, 18, 4, 0, 0, pytz.UTC),
+            ),
+        ),
+        (
+            "1 year",
+            SampleWindow(
+                start=datetime(2024, 1, 28, 18, 4, 0, 0, pytz.UTC),
+                end=datetime(2025, 1, 28, 18, 4, 0, 0, pytz.UTC),
+            ),
+        ),
+        (
+            "4 YEARS",
+            SampleWindow(
+                start=datetime(2021, 1, 28, 18, 4, 0, 0, pytz.UTC),
+                end=datetime(2025, 1, 28, 18, 4, 0, 0, pytz.UTC),
+            ),
+        ),
+        (
+            "1 YEAR",
+            SampleWindow(
+                start=datetime(2024, 1, 28, 18, 4, 0, 0, pytz.UTC),
+                end=datetime(2025, 1, 28, 18, 4, 0, 0, pytz.UTC),
+            ),
+        ),
+        (
+            "4 months",
+            SampleWindow(
+                start=datetime(2024, 9, 28, 18, 4, 0, 0, pytz.UTC),
+                end=datetime(2025, 1, 28, 18, 4, 0, 0, pytz.UTC),
+            ),
+        ),
+        (
+            "1 month",
+            SampleWindow(
+                start=datetime(2024, 12, 28, 18, 4, 0, 0, pytz.UTC),
+                end=datetime(2025, 1, 28, 18, 4, 0, 0, pytz.UTC),
+            ),
+        ),
+        (
+            "4 MONTHS",
+            SampleWindow(
+                start=datetime(2024, 9, 28, 18, 4, 0, 0, pytz.UTC),
+                end=datetime(2025, 1, 28, 18, 4, 0, 0, pytz.UTC),
+            ),
+        ),
+        (
+            "1 MONTH",
+            SampleWindow(
+                start=datetime(2024, 12, 28, 18, 4, 0, 0, pytz.UTC),
+                end=datetime(2025, 1, 28, 18, 4, 0, 0, pytz.UTC),
+            ),
+        ),
+        (
+            "4 days",
+            SampleWindow(
+                start=datetime(2025, 1, 24, 18, 4, 0, 0, pytz.UTC),
+                end=datetime(2025, 1, 28, 18, 4, 0, 0, pytz.UTC),
+            ),
+        ),
+        (
+            "1 day",
+            SampleWindow(
+                start=datetime(2025, 1, 27, 18, 4, 0, 0, pytz.UTC),
+                end=datetime(2025, 1, 28, 18, 4, 0, 0, pytz.UTC),
+            ),
+        ),
+        (
+            "4 DAYS",
+            SampleWindow(
+                start=datetime(2025, 1, 24, 18, 4, 0, 0, pytz.UTC),
+                end=datetime(2025, 1, 28, 18, 4, 0, 0, pytz.UTC),
+            ),
+        ),
+        (
+            "1 DAY",
+            SampleWindow(
+                start=datetime(2025, 1, 27, 18, 4, 0, 0, pytz.UTC),
+                end=datetime(2025, 1, 28, 18, 4, 0, 0, pytz.UTC),
+            ),
+        ),
+        (
+            "4 hours",
+            SampleWindow(
+                start=datetime(2025, 1, 28, 14, 4, 0, 0, pytz.UTC),
+                end=datetime(2025, 1, 28, 18, 4, 0, 0, pytz.UTC),
+            ),
+        ),
+        (
+            "1 hour",
+            SampleWindow(
+                start=datetime(2025, 1, 28, 17, 4, 0, 0, pytz.UTC),
+                end=datetime(2025, 1, 28, 18, 4, 0, 0, pytz.UTC),
+            ),
+        ),
+        (
+            "4 HOURS",
+            SampleWindow(
+                start=datetime(2025, 1, 28, 14, 4, 0, 0, pytz.UTC),
+                end=datetime(2025, 1, 28, 18, 4, 0, 0, pytz.UTC),
+            ),
+        ),
+        (
+            "1 HOUR",
+            SampleWindow(
+                start=datetime(2025, 1, 28, 17, 4, 0, 0, pytz.UTC),
+                end=datetime(2025, 1, 28, 18, 4, 0, 0, pytz.UTC),
+            ),
+        ),
+        (
+            "1 week",
+            DbtRuntimeError(
+                "Invalid grain size 'week'. Must be one of ['hour', 'day', 'month', 'year', 'hours', 'days', 'months', 'years']."
+            ),
+        ),
+        ("an hour", DbtRuntimeError("Unable to convert 'an' to an integer.")),
+        (
+            "3",
+            DbtRuntimeError(
+                "Cannot load SAMPLE_WINDOW from '3'. Must be of form 'DAYS_INT GRAIN_SIZE'."
+            ),
+        ),
+        (
+            "True",
+            DbtRuntimeError(
+                "Cannot load SAMPLE_WINDOW from 'True'. Must be of form 'DAYS_INT GRAIN_SIZE'."
+            ),
+        ),
+        ("days 3", DbtRuntimeError("Unable to convert 'days' to an integer.")),
+        (
+            "{}",
+            DbtRuntimeError(
+                "Cannot load SAMPLE_WINDOW from '{}'. Must be of form 'DAYS_INT GRAIN_SIZE'."
+            ),
+        ),
+    ],
+)
+@freezegun.freeze_time("2025-01-28T18:04:0Z")
+def test_from_relative_string(
+    relative_string: str, expected_result: Union[SampleWindow, Exception]
+):
+    try:
+        result = SampleWindow.from_relative_string(relative_string)
+        assert result == expected_result
+    except Exception as e:
+        assert str(e) == str(expected_result)