prop/test/microwaveprop/weather/nexrad_client_test.exs
Graham McIntire cb8445f329
fix: resolve 158/183 credo --strict warnings
- Add 17 missing @spec annotations (layouts, error_json, error_html, skewt_svg)
- Move 12+ nested alias/import/require to module top level
- Add phx-change/id attributes to 11 raw HTML <form> tags
- Remove 4 unused LiveView assigns (:bounds, :data_provider)
- Add 3 missing doctest references (HrrrNativeClient, BulkFetch, Accounts)
- Break 2 long lines (path_compute.ex:382)
- Strengthen weak test assertions (is_binary→byte_size, is_list→!=[])
- Replace Module.concat with Module.safe_concat (2 occurrences)
- Replace length/1 > 0 with list != [] (9 occurrences)
- Remove no-op assert true, fix no-assertion tests

Remaining: 24 socket.assigns introspection warnings (deliberate test
pattern for observable behavior testing), 1 formatter-resistant long
line, 3 app-code usage warnings.
2026-06-12 15:47:15 -05:00

524 lines
17 KiB
Elixir

defmodule Microwaveprop.Weather.NexradClientTest do
use ExUnit.Case, async: false
use ExUnitProperties
alias Microwaveprop.Weather.NexradCache
alias Microwaveprop.Weather.NexradClient
describe "fetch_rain_cells/4 with injected http_get" do
setup do
prev = Application.get_env(:microwaveprop, :nexrad_http_get)
NexradCache.clear()
on_exit(fn ->
if prev,
do: Application.put_env(:microwaveprop, :nexrad_http_get, prev),
else: Application.delete_env(:microwaveprop, :nexrad_http_get)
NexradCache.clear()
end)
:ok
end
test "propagates an HTTP non-200 status from the IEM archive" do
Application.put_env(:microwaveprop, :nexrad_http_get, fn _url, _opts ->
{:ok, %{status: 404, body: ""}}
end)
assert {:error, "NEXRAD n0q HTTP 404"} = NexradClient.fetch_rain_cells(32.9, -97.0, 50.0, 25.0)
end
test "propagates a transport error" do
Application.put_env(:microwaveprop, :nexrad_http_get, fn _url, _opts ->
{:error, :timeout}
end)
assert {:error, :timeout} = NexradClient.fetch_rain_cells(32.9, -97.0, 50.0, 25.0)
end
end
describe "round_to_5min/1" do
test "rounds down to nearest 5-minute boundary" do
dt = ~U[2022-08-20 14:07:32Z]
assert NexradClient.round_to_5min(dt) == ~U[2022-08-20 14:05:00Z]
end
test "already on a 5-minute boundary stays unchanged" do
dt = ~U[2022-08-20 14:10:00Z]
assert NexradClient.round_to_5min(dt) == ~U[2022-08-20 14:10:00Z]
end
test "59 minutes rounds down to 55" do
dt = ~U[2022-08-20 14:59:59Z]
assert NexradClient.round_to_5min(dt) == ~U[2022-08-20 14:55:00Z]
end
end
describe "frame_url/1" do
test "builds correct IEM n0q URL from datetime" do
dt = ~U[2022-08-20 14:05:00Z]
url = NexradClient.frame_url(dt)
assert url ==
"https://mesonet.agron.iastate.edu/archive/data/2022/08/20/GIS/uscomp/n0q_202208201405.png"
end
test "pads single-digit month and day" do
dt = ~U[2022-01-05 03:00:00Z]
url = NexradClient.frame_url(dt)
assert url ==
"https://mesonet.agron.iastate.edu/archive/data/2022/01/05/GIS/uscomp/n0q_202201050300.png"
end
end
describe "latlon_to_pixel/2" do
test "converts coordinates to pixel positions" do
# Top-left corner: lat=50, lon=-126
{x, y} = NexradClient.latlon_to_pixel(50.0, -126.0)
assert x == 0
assert y == 0
end
test "bottom-right corner" do
# lon = -65 -> x = (-65 - -126) / 0.005 = 61 / 0.005 = 12200
# lat = 23 -> y = (50 - 23) / 0.005 = 27 / 0.005 = 5400
{x, y} = NexradClient.latlon_to_pixel(23.0, -65.0)
assert x == 12_200
assert y == 5400
end
test "DFW area" do
# DFW: lat ~32.9, lon ~-97.0
{x, y} = NexradClient.latlon_to_pixel(32.9, -97.0)
# x = (-97 - -126) / 0.005 = 29 / 0.005 = 5800
assert x == 5800
# y = (50 - 32.9) / 0.005 = 17.1 / 0.005 = 3420
assert y == 3420
end
end
describe "extract_box/4" do
test "extracts stats from a box of pixel values" do
# Create a simple 100x100 image (all zeros except a small region)
width = 100
height = 100
pixels = :binary.copy(<<0>>, width * height)
# Put some non-zero values around pixel (50, 50) - a 5x5 block
pixels =
Enum.reduce(48..52, pixels, fn y, acc ->
Enum.reduce(48..52, acc, fn x, inner_acc ->
offset = y * width + x
<<pre::binary-size(offset), _::8, post::binary>> = inner_acc
<<pre::binary, 120::8, post::binary>>
end)
end)
result = NexradClient.extract_box(pixels, width, 50, 50, 5)
assert result.pixel_count == 25
assert result.max_reflectivity_dbz > 0
assert result.mean_reflectivity_dbz > 0
assert result.texture_variance == 0.0
end
test "returns zeros for an empty box" do
width = 100
height = 100
pixels = :binary.copy(<<0>>, width * height)
result = NexradClient.extract_box(pixels, width, 50, 50, 5)
assert result.pixel_count == 0
assert result.mean_reflectivity_dbz == 0.0
assert result.max_reflectivity_dbz == 0.0
assert result.texture_variance == 0.0
end
test "computes texture variance for mixed values" do
width = 100
height = 100
pixels = :binary.copy(<<0>>, width * height)
# Place alternating values: half 100, half 200
pixels =
Enum.reduce(48..52, pixels, fn y, acc ->
Enum.reduce(48..52, acc, fn x, inner_acc ->
offset = y * width + x
value = if rem(x + y, 2) == 0, do: 100, else: 200
<<pre::binary-size(offset), _::8, post::binary>> = inner_acc
<<pre::binary, value::8, post::binary>>
end)
end)
result = NexradClient.extract_box(pixels, width, 50, 50, 5)
assert result.pixel_count == 25
# Variance should be non-zero since we have mixed values
assert result.texture_variance > 0.0
end
test "handles box at image boundary by clamping" do
width = 100
height = 100
pixels = :binary.copy(<<50>>, width * height)
# Corner case: near edge
result = NexradClient.extract_box(pixels, width, 2, 2, 25)
# Should not crash; pixel_count depends on how many pixels are in bounds
assert result.pixel_count > 0
end
end
describe "fetch_decoded_frame/1 caching" do
# Minimal 20x20 indexed-color PNG identical to the NexradWorkerTest
# fixture. Used here just to give the decoder something valid to
# chew on; caching semantics don't care about the contents.
defp minimal_png(width \\ 20, height \\ 20) do
signature = <<137, 80, 78, 71, 13, 10, 26, 10>>
ihdr_data = <<width::32, height::32, 8, 3, 0, 0, 0>>
ihdr_chunk = <<byte_size(ihdr_data)::32, "IHDR", ihdr_data::binary, 0::32>>
raw = for _ <- 1..height, into: <<>>, do: <<0, 0::size(width)-unit(8)>>
compressed = :zlib.compress(raw)
idat_chunk = <<byte_size(compressed)::32, "IDAT", compressed::binary, 0::32>>
iend_chunk = <<0::32, "IEND", 0::32>>
signature <> ihdr_chunk <> idat_chunk <> iend_chunk
end
setup do
NexradCache.clear()
on_exit(fn -> NexradCache.clear() end)
:ok
end
test "first call fetches+decodes; second call for same 5-min bucket is served from cache" do
test_pid = self()
Req.Test.stub(NexradClient, fn conn ->
send(test_pid, :http_fetched)
Plug.Conn.send_resp(conn, 200, minimal_png())
end)
ts = ~U[2022-08-20 14:07:00Z]
{:ok, pixels1, width1} = NexradClient.fetch_decoded_frame(ts)
{:ok, pixels2, width2} = NexradClient.fetch_decoded_frame(ts)
# The cache is keyed on the 5-min rounded timestamp, so a
# second call within the same bucket reuses the decoded pixels.
assert pixels1 == pixels2
assert width1 == width2
assert_received :http_fetched
refute_received :http_fetched
end
test "different 5-min buckets hit the network separately" do
test_pid = self()
Req.Test.stub(NexradClient, fn conn ->
send(test_pid, :http_fetched)
Plug.Conn.send_resp(conn, 200, minimal_png())
end)
{:ok, _, _} = NexradClient.fetch_decoded_frame(~U[2022-08-20 14:05:00Z])
{:ok, _, _} = NexradClient.fetch_decoded_frame(~U[2022-08-20 14:10:00Z])
assert_received :http_fetched
assert_received :http_fetched
end
end
describe "pixel_to_dbz/1" do
test "value 0 maps to 0 (no echo)" do
assert NexradClient.pixel_to_dbz(0) == 0.0
end
test "value 255 maps to approximately 95 dBZ" do
dbz = NexradClient.pixel_to_dbz(255)
assert_in_delta dbz, 95.0, 1.0
end
test "mid-range value produces reasonable dBZ" do
dbz = NexradClient.pixel_to_dbz(128)
assert dbz > 0.0
assert dbz < 95.0
end
property "is monotonic non-decreasing across [1, 255]" do
check all(
a <- integer(1..254),
delta <- integer(0..254)
) do
b = min(a + delta, 255)
assert NexradClient.pixel_to_dbz(a) <= NexradClient.pixel_to_dbz(b)
end
end
property "output is in [-30.0, 95.0] for any byte value [1, 255]" do
check all(value <- integer(1..255)) do
dbz = NexradClient.pixel_to_dbz(value)
assert dbz >= -30.0
assert dbz <= 95.0 + 1.0e-9
end
end
end
describe "latlon_to_pixel/2 invariants" do
property "matching lat/lon corners snap to pixel corners exactly" do
# The CONUS grid is a 12201x5401 frame anchored at (50N, -126W)
# with 0.005deg resolution. Every cell center whose (lat, lon)
# is aligned with the grid must round-trip to the integer pixel
# coordinates the module's constants imply.
check all(
x <- integer(0..12_200),
y <- integer(0..5400)
) do
lat = 50.0 - y * 0.005
lon = -126.0 + x * 0.005
{px, py} = NexradClient.latlon_to_pixel(lat, lon)
assert px == x
assert py == y
end
end
end
describe "fetch_frame/2" do
setup do
NexradCache.clear()
on_exit(fn -> NexradCache.clear() end)
:ok
end
test "returns observations when HTTP 200 with valid PNG" do
Req.Test.stub(NexradClient, fn conn ->
Plug.Conn.send_resp(conn, 200, minimal_png(30, 30))
end)
# DFW area within the 30x30 image
{:ok, observations} = NexradClient.fetch_frame(~U[2022-08-20 14:05:00Z], [{32.9, -97.0}])
assert length(observations) == 1
obs = hd(observations)
assert_in_delta obs.lat, 32.9, 0.01
assert_in_delta obs.lon, -97.0, 0.01
assert obs.pixel_count == 0
end
test "HTTP 500 returns {:error, _} with status message" do
Req.Test.stub(NexradClient, fn conn ->
Plug.Conn.send_resp(conn, 500, "boom")
end)
assert {:error, msg} = NexradClient.fetch_frame(~U[2022-08-20 14:05:00Z], [{32.9, -97.0}])
assert msg =~ "500"
end
test "HTTP 404 returns {:error, _}" do
Req.Test.stub(NexradClient, fn conn ->
Plug.Conn.send_resp(conn, 404, "not found")
end)
assert {:error, msg} = NexradClient.fetch_frame(~U[2022-08-20 14:05:00Z], [{32.9, -97.0}])
assert msg =~ "404"
end
test "transport timeout bubbles up as {:error, _}" do
Req.Test.stub(NexradClient, fn conn ->
Req.Test.transport_error(conn, :timeout)
end)
assert {:error, _reason} = NexradClient.fetch_frame(~U[2022-08-20 14:05:00Z], [{32.9, -97.0}])
end
end
describe "fetch_decoded_frame/1 error paths" do
setup do
NexradCache.clear()
on_exit(fn -> NexradCache.clear() end)
:ok
end
test "HTTP 503 returns {:error, _} and does not populate cache" do
Req.Test.stub(NexradClient, fn conn ->
Plug.Conn.send_resp(conn, 503, "unavailable")
end)
ts = ~U[2022-08-20 14:05:00Z]
assert {:error, msg} = NexradClient.fetch_decoded_frame(ts)
assert msg =~ "503"
# Cache must not carry forward a 503 — next call must hit the network
# again (the stub is still in place, so we still get the same error).
assert {:error, _} = NexradClient.fetch_decoded_frame(ts)
end
test "malformed PNG body returns {:error, _} from the decoder" do
Req.Test.stub(NexradClient, fn conn ->
Plug.Conn.send_resp(conn, 200, "not a png")
end)
assert {:error, reason} = NexradClient.fetch_decoded_frame(~U[2022-08-20 14:05:00Z])
# decode_png_to_pixels wraps any exception into this string
assert byte_size(reason) > 0
assert reason =~ "PNG decode failed"
end
end
describe "frame_url/1 round-trip property" do
property "url embeds the date path and a 12-digit timestamp for any rounded 5-min input" do
check all(
year <- integer(2015..2030),
month <- integer(1..12),
day <- integer(1..28),
hour <- integer(0..23),
minute_bucket <- integer(0..11)
) do
dt = %DateTime{
year: year,
month: month,
day: day,
hour: hour,
minute: minute_bucket * 5,
second: 0,
microsecond: {0, 0},
std_offset: 0,
utc_offset: 0,
zone_abbr: "UTC",
time_zone: "Etc/UTC"
}
url = NexradClient.frame_url(dt)
date_path =
"#{year}/#{String.pad_leading(Integer.to_string(month), 2, "0")}/" <>
String.pad_leading(Integer.to_string(day), 2, "0")
file_ts =
[year, month, day, hour, minute_bucket * 5]
|> Enum.map(&Integer.to_string/1)
|> Enum.zip([4, 2, 2, 2, 2])
|> Enum.map_join(fn {str, w} -> String.pad_leading(str, w, "0") end)
assert String.contains?(url, date_path)
assert String.contains?(url, "n0q_#{file_ts}.png")
end
end
end
describe "extract_box/5 edge cases" do
test "box partially off the left edge returns whatever pixels fall inside" do
# 4-row x 10-col frame, every pixel hot.
pixels = :binary.copy(<<128>>, 40)
# Centre x=0 rarr x_min=0, x_max=2. Centre y=0 rarr y_min=0, y_max=2.
result = NexradClient.extract_box(pixels, 10, 0, 0, 2)
assert result.pixel_count > 0
assert result.max_reflectivity_dbz > 0.0
end
test "box entirely off the right edge returns no-data (no pixels)" do
pixels = :binary.copy(<<128>>, 40)
# width=10, cx=50 rarr x_min=48, x_max=9 rarr empty range after clamp.
result = NexradClient.extract_box(pixels, 10, 50, 2, 2)
assert result.pixel_count == 0
assert result.mean_reflectivity_dbz == 0.0
assert result.max_reflectivity_dbz == 0.0
assert result.texture_variance == 0.0
end
test "zero pixels in box yields the no-echo stats tuple" do
pixels = :binary.copy(<<0>>, 40)
result = NexradClient.extract_box(pixels, 10, 5, 2, 2)
# Every pixel is 0 rarr none enter the filtered dbz_values list.
assert result.pixel_count == 0
assert result.mean_reflectivity_dbz == 0.0
end
end
describe "fetch_decoded_frame/1 cache population" do
# Minimal 20x20 indexed-color PNG identical to the earlier fixture.
defp tiny_png(width \\ 20, height \\ 20) do
signature = <<137, 80, 78, 71, 13, 10, 26, 10>>
ihdr_data = <<width::32, height::32, 8, 3, 0, 0, 0>>
ihdr_chunk = <<byte_size(ihdr_data)::32, "IHDR", ihdr_data::binary, 0::32>>
raw = for _ <- 1..height, into: <<>>, do: <<0, 0::size(width)-unit(8)>>
compressed = :zlib.compress(raw)
idat_chunk = <<byte_size(compressed)::32, "IDAT", compressed::binary, 0::32>>
iend_chunk = <<0::32, "IEND", 0::32>>
signature <> ihdr_chunk <> idat_chunk <> iend_chunk
end
setup do
NexradCache.clear()
on_exit(fn -> NexradCache.clear() end)
:ok
end
test "successful fetch populates the cache (second fetch is a :hit)" do
Req.Test.stub(NexradClient, fn conn ->
Plug.Conn.send_resp(conn, 200, tiny_png())
end)
ts = ~U[2022-08-20 14:07:00Z]
rounded = NexradClient.round_to_5min(ts)
assert NexradCache.fetch(rounded) == :miss
{:ok, _pixels, _width} = NexradClient.fetch_decoded_frame(ts)
assert {:ok, _pixels2, _width2} = NexradCache.fetch(rounded)
end
end
describe "fetch_decoded_frame/1 empty body" do
setup do
NexradCache.clear()
on_exit(fn -> NexradCache.clear() end)
:ok
end
test "zero-byte 200 response surfaces a PNG decode error" do
Req.Test.stub(NexradClient, fn conn ->
Plug.Conn.send_resp(conn, 200, "")
end)
assert {:error, reason} = NexradClient.fetch_decoded_frame(~U[2022-08-20 14:05:00Z])
assert byte_size(reason) > 0
assert reason =~ "PNG decode failed"
end
end
describe "frame_url/1 year boundaries" do
test "Dec 31 23:55 produces a URL anchored in the old year" do
dt = ~U[2022-12-31 23:55:00Z]
url = NexradClient.frame_url(dt)
assert url =~ "2022/12/31"
assert url =~ "n0q_202212312355.png"
refute url =~ "2023/"
end
test "Jan 1 00:00 of the following year flips cleanly into the new year" do
dt = ~U[2023-01-01 00:00:00Z]
url = NexradClient.frame_url(dt)
assert url =~ "2023/01/01"
assert url =~ "n0q_202301010000.png"
refute url =~ "2022/"
end
test "rounding 23:59 Dec 31 stays in Dec 31 (no rollover via round_to_5min)" do
dt = ~U[2022-12-31 23:59:59Z]
rounded = NexradClient.round_to_5min(dt)
assert rounded.year == 2022
assert rounded.month == 12
assert rounded.day == 31
assert rounded.hour == 23
assert rounded.minute == 55
url = NexradClient.frame_url(rounded)
assert url =~ "2022/12/31"
end
end
end