test: test cache get with space_name == nil [TO SQUASH]

Author: ligurio

test/cache_test.lua

@@ -230,3 +230,16 @@ function g.test_cache_space_updated_name()
     t.assert_type(id, 'number')
     t.assert_equals(id, 44)
 end
+
+function g.test_cache_nil_space()
+    local sharding_func_first = 'sharding_func_first'
+    rawset(_G, sharding_func_first, function(key) return key + 1 end)
+    rawset(_G, 'sharding_func_second', function(key) return key + 2 end)
+    g.schema.spaces.space.sharding_func = sharding_func_first
+    local ok, err = ddl.set_schema(g.schema)
+    t.assert_equals(err, nil)
+    t.assert_equals(ok, true)
+
+    local res = cache.internal.get()
+    t.assert_equals(res, nil)
+end