Add UI tests for macros error message

testing/tests/ui/macro.rs

@@ -0,0 +1,27 @@
+use askama::Template;
+
+#[derive(Template)]
+#[template(source = "{%- macro thrice(param) -%}
+{{ param }}
+{%- endmacro -%}
+
+{%- call thrice(2, 3) -%}", ext = "html")]
+struct InvalidNumberOfArgs;
+
+#[derive(Template)]
+#[template(source = "{%- macro thrice(param, param2) -%}
+{{ param }} {{ param2 }}
+{%- endmacro -%}
+
+{%- call thrice() -%}", ext = "html")]
+struct InvalidNumberOfArgs2;
+
+#[derive(Template)]
+#[template(source = "{%- macro thrice() -%}
+{%- endmacro -%}
+
+{%- call thrice(1, 2) -%}", ext = "html")]
+struct InvalidNumberOfArgs3;
+
+fn main() {
+}

testing/tests/ui/macro.stderr

@@ -0,0 +1,23 @@
+error: macro "thrice" expected 1 argument, found 2
+ --> tests/ui/macro.rs:3:10
+  |
+3 | #[derive(Template)]
+  |          ^^^^^^^^
+  |
+  = note: this error originates in the derive macro `Template` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: macro "thrice" expected 2 arguments, found 0
+  --> tests/ui/macro.rs:11:10
+   |
+11 | #[derive(Template)]
+   |          ^^^^^^^^
+   |
+   = note: this error originates in the derive macro `Template` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: macro "thrice" expected 0 arguments, found 2
+  --> tests/ui/macro.rs:19:10
+   |
+19 | #[derive(Template)]
+   |          ^^^^^^^^
+   |
+   = note: this error originates in the derive macro `Template` (in Nightly builds, run with -Z macro-backtrace for more info)