…s, without explicitly defining metadata

Combined CDSAPI requests will return a single combined netcdf; set
cleanup=false to keep the "_tmp_multi_<datetime>_*" files

Note: inpainting is now turned OFF for 2D data -- the reanalysis data
should be complete and turning on inpainting would artificially fill in
data that should be masked (e.g., ocean quantities over land)

Tested for 2D (single levels) and 3D (pressure levels)

to disambiguate from ERA5PressureLevels*

Clipped field will match downloaded bounding box, tested with ERA5

rename levels -> pressure_levels for clarity

…to eq/era5_pressure_levels

Per @glwagner's review: a `Field{Nothing, Nothing, Center}` represents
the same per-level pressure values as the previous `CenterField` but
without copying across the full horizontal grid. Use `set!` for the
column assignment, drop the per-k loop, and let the field's eltype
follow the grid (no more hardcoded `Float32`).

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

Surface-level testsets each downloaded `2m_temperature` then removed it,
forcing the next testset to re-download the same bytes — three CDS
round-trips for one fixture. Keep the pre-clean only in the testset
that's testing the download path itself; let downstream testsets reuse
the file and run cleanup in the last consumer.

Pressure-level "Geopotential height conversion" pre-cleaned the
`geopotential_...nc` that the previous testset's `z_interfaces`
side-effect leaves on disk, then re-downloaded it. Drop the pre-clean
and the redundant explicit `download_dataset(meta_z)` call (Field()
already downloads if needed).

Net: surface round-trips drop 3 → 1, geopotential round-trips drop 2 → 1.

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

…to eq/era5_pressure_levels

Cover the parts of `src/DataWrangling/ERA5/ERA5_single_levels.jl`
that the integration tests don't exercise directly: hourly `all_dates`
step (mirrors the existing monthly test), the API/netcdf variable-name
dicts staying in sync, the `available_variables` / `dataset_variable_name`
dispatch (catches the easy swap between API catalog name and netcdf
short name), `default_inpainting` returning `nothing` (the wrong value
here silently makes Field construction expensive), and `metadata_prefix`
filename construction across the single-date / multi-date / no-region
branches plus filename-safety transformations.

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

Extract `_group_by_calendar_day(datetimes)` from the inline
comprehensions in two `download_dataset` overloads so the grouping
logic is testable in isolation. Test boundary cases:

- 00:00 belongs to its own day, not the previous one
- multi-day interleaved input
- duplicate datetimes are preserved
- single-element input

Also add tests for the `skip_existing=true` short-circuit in three
multi-file paths (multi-variable pressure-level, single-variable
multi-date, multi-variable multi-date). Pre-create the expected output
files in a tempdir and assert each path returns without invoking
CDSAPI; if the short-circuit ever regresses the test will throw a
credentials/network error and fail loudly.

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

…to eq/era5_pressure_levels

…ls, and CDSAPI ext

Cover several pure functions and dispatch overloads that the integration tests
either skip or don't exercise directly. Each test is no-network and self-contained.

`metadata_field.jl`:
- `restrict` (BoundingBox grid construction): identity, half-domain, small bbox,
  off-origin bbox, and the `Nothing` pass-through dispatch.
- `restrict_location` for all three region kinds (`BoundingBox` / `Nothing` /
  `Column`), confirming the Column path reduces horizontal locations to `Nothing`.

`ERA5_pressure_levels.jl`:
- Constructors sort levels descending: pass ASCENDING input
  (`[500, 850]hPa`) so the test fails if `sort(...; rev=true)` regresses to a
  no-op or different order. Covered for both Hourly and Monthly variants.
- `stagger`: pure function that converts ascending centers to Nz+1 staggered
  interfaces. Covers two-element evenly-spaced, three-element evenly-spaced,
  and three-element irregular cases (verifies extrapolation formula at top/bot
  and midpoint formula in the interior).

`NumericalEarthCDSAPIExt.jl`:
- `is_zip`: ZIP magic header detected, non-magic bytes rejected, short
  (<4 byte) files rejected.
- `foreach_nc`: non-zip path calls `f` exactly once with the input path; zip
  path extracts and visits each `.nc`, ignoring non-`.nc` entries.

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