implement safe_cast + add tests for array, map, named_struct for unit…

… testing

dbt/include/spark/macros/utils/safe_cast.sql

@@ -0,0 +1,11 @@
+{% macro spark__safe_cast(field, type) %}
+{%- if cast_from_string_unsupported_for(type) and field is string -%}
+    cast({{field.strip('"').strip("'")}} as {{type}})
+{%- else -%}
+    safe_cast({{field}} as {{type}})
+{%- endif -%}
+{% endmacro %}
+
+{% macro cast_from_string_unsupported_for(type) %}
+    {{ return(type.lower().startswith('struct') or type.lower().startswith('array') or type.lower().startswith('map')) }}
+{% endmacro %}

tests/functional/adapter/unit_testing/test_unit_testing.py

@@ -17,9 +17,12 @@ def data_types(self):
             ["true", "true"],
             ["date '2011-11-11'", "2011-11-11"],
             ["timestamp '2013-11-03 00:00:00-0'", "2013-11-03 00:00:00-0"],
-            # ["map(struct('Hello', 'World'), 'Greeting')", '''"map(struct('Hello', 'World'), 'Greeting')"'''],
-            # ['named_struct("a", 1, "b", 2, "c", 3)', """'named_struct("a", 1, "b", 2, "c", 3)'"""],
-            # ["array(1, 2, 3)", "'array(1, 2, 3)'"],
+            ["array(1, 2, 3)", "'array(1, 2, 3)'"],
+            [
+                "map('10', 't', '15', 'f', '20', NULL)",
+                """'map("10", "t", "15", "f", "20", NULL)'""",
+            ],
+            ['named_struct("a", 1, "b", 2, "c", 3)', """'named_struct("a", 1, "b", 2, "c", 3)'"""],
         ]