Add test for rust module calls

Author: RoyalIcing

test/components_guide/rustler/math_test.exs

@@ -0,0 +1,25 @@
+defmodule ComponentsGuide.Rustler.MathTest do
+  use ExUnit.Case, async: true
+
+  alias ComponentsGuide.Rustler.Math
+
+  test "add/2" do
+    assert Math.add(3, 4) == 7
+  end
+
+  test "reverse_string/1" do
+    assert Math.reverse_string("abcd") == "dcba"
+  end
+
+  test "wasm_example/2" do
+    wasm_source = """
+    (module
+      (func (export "answer") (result i32)
+       i32.const 42
+      )
+    )
+    """
+
+    assert Math.wasm_example(wasm_source, "answer") == 42
+  end
+end