filter null ocean colour data

Author: twsearle

src/tests/testinput/CMakeLists.txt

@@ -17,6 +17,7 @@ list( APPEND orcajedi_test_input
   hofx3d_nc_ssh_amm1r.yaml
   odb_sic_query.yaml
   odb_sic_mapping.yaml
+  odb_col_chl_query_filter_null.yaml
   test_name_map.yaml
   dirac.yaml
   3dvar_sic.yaml

src/tests/testinput/odb_col_chl_query_filter_null.yaml

@@ -0,0 +1,15 @@
+where:
+  varno: [288,]
+query: initial_obsvalue is not null
+variables:
+- name: receipt_time
+- name: receipt_date
+- name: initial_obsvalue
+- name: instrument_type
+- name: lat
+- name: lon
+- name: date
+- name: time
+- name: ops_obsgroup
+- name: varno
+- name: seqno