Add extra sanity check for ooe_tbl test

Compare the retrieved semi-major axis value (in AU) when the AU value
retrieved "manually" from the web interface for the same date
(2023-01-01).

test/runtests.jl

@@ -97,26 +97,36 @@ end
 
 @testset "Osculating Orbital Elements table generation: ooe_tbl" begin
     # Generate tables and save output to JWST.txt
-    t_start = DateTime(2024, 3, 13)
-    t_stop = Date(2024, 3, 14)
+    t_start = DateTime(2023, 1, 1)
+    t_stop = Date(2023, 1, 2)
     δt = Hour(1)
-    local_file = ooe_tbl("JWST", t_start, t_stop, δt; CSV_FORMAT = true,
-                         FILENAME = "jwst.csv", CENTER = "SSB")
+    local_file = ooe_tbl("JWST", t_start, t_stop, δt; FILENAME = "jwst.csv",
+                         CSV_FORMAT = true, CENTER = "SSB", OUT_UNITS="AU-D")
 
     @test isfile(local_file)
 
-    jwst = ooe_tbl("JWST", t_start, t_stop, δt; CSV_FORMAT = true, CENTER = "SSB")
+    jwst = ooe_tbl("JWST", t_start, t_stop, δt;
+                   CSV_FORMAT = true, CENTER = "SSB", OUT_UNITS="AU-D")
 
     x = readlines(local_file)
     y = split(chomp(jwst), "\n")
 
     @test length(x) == length(y)
     # Find lines that differ
     diffinds = findall(x .!= y)
-    # The only lines that should differ start with "Ephemeris / API_USER" and
+    # The only line(s) that should differ start with "Ephemeris / API_USER" and
     # contain time of retrieval.
     @test all(startswith("Ephemeris / API_USER"), y[diffinds])
 
+    # Test that A (semi-major axis) for t_start has expected value
+    soe = findfirst(==("\$\$SOE"), y)
+    a_fetched = parse(Float64, split(y[soe+1], ',')[12])
+    a_expected = 1.028281028256704E+00 # for 2023-01-01 (retrieved 2024-04-02)
+
+    # This test may fail if the "DEFINITIVE_EPHEMERIS" for past dates are ever
+    # updated/changed.
+    @test a_fetched ≈ a_expected
+
     rm(local_file)
 end