Increase quantile summary test coverage

Author: NelsonVides

src/metrics/prometheus_quantile_summary.erl

@@ -494,10 +494,10 @@ create_summary(Name, Help, Data) ->
 
 validate_error(Error) when is_number(Error), 0.0 < Error, Error < 100.0 ->
     ok;
-validate_error(_Error) ->
-    erlang:error({invalid_error, "Error should be a percentage point in (0,100)"}).
+validate_error(Error) ->
+    erlang:error({invalid_error, Error, "Error should be a percentage point in (0,100)"}).
 
 validate_bound(Bound) when is_integer(Bound), 0 < Bound ->
     ok;
-validate_bound(_Bound) ->
-    erlang:error({invalid_bound, "Bound should be a positive integer"}).
+validate_bound(Bound) ->
+    erlang:error({invalid_bound, Bound, "Bound should be a positive integer"}).

test/eunit/metric/prometheus_quantile_summary_tests.erl

@@ -19,6 +19,8 @@ prometheus_format_test_() ->
         fun test_deregister/1,
         fun test_remove/1,
         fun test_default_value/1,
+        fun test_values_when_empty/1,
+        fun test_values_when_non_existing/1,
         fun test_values/1,
         fun test_collector1/1,
         fun test_collector2/1,
@@ -85,6 +87,23 @@ test_errors(_) ->
             {invalid_metric_help, 12, "metric help is not a string"},
             prometheus_quantile_summary:new([{name, "qwe"}, {help, 12}])
         ),
+        ?_assertError(
+            {invalid_bound, 3.141592, "Bound should be a positive integer"},
+            prometheus_quantile_summary:new([
+                {name, "qwe"},
+                {bound, 3.141592},
+                {help, ""}
+            ])
+        ),
+        ?_assertError(
+            {invalid_error, 101, "Error should be a percentage point in (0,100)"},
+            prometheus_quantile_summary:new([
+                {name, "qwe"},
+                {error, 101},
+                {labels, ["qua", "quantile"]},
+                {help, ""}
+            ])
+        ),
         %% mf/arity errors
         ?_assertError(
             {unknown_metric, default, unknown_metric},
@@ -400,6 +419,27 @@ test_default_value(_) ->
         ?_assertMatch({0, 0, []}, SomethingValue)
     ].
 
+test_values_when_empty(_) ->
+    prometheus_quantile_summary:new([
+        {name, orders_summary},
+        {labels, [department]},
+        {help, "Track orders count/total sum"}
+    ]),
+    [
+        ?_assertMatch(
+            [],
+            lists:sort(prometheus_quantile_summary:values(default, orders_summary))
+        )
+    ].
+
+test_values_when_non_existing(_) ->
+    [
+        ?_assertMatch(
+            [],
+            lists:sort(prometheus_quantile_summary:values(default, orders_summary))
+        )
+    ].
+
 test_values(_) ->
     prometheus_quantile_summary:new([
         {name, orders_summary},
@@ -408,7 +448,6 @@ test_values(_) ->
     ]),
     prometheus_quantile_summary:observe(orders_summary, [electronics], 765.5),
     prometheus_quantile_summary:observe(orders_summary, [groceries], 112.3),
-
     [
         ?_assertMatch(
             [