From cac6b4ae012a9222086559d6b27f2848c4e0d3dc Mon Sep 17 00:00:00 2001
From: Ivan Enderlin <ivan.enderlin@hoa-project.net>
Date: Tue, 3 Mar 2020 17:04:26 +0100
Subject: [PATCH] test(interface-types) Add test cases for errors.

---
 .../instructions/lowering_lifting.rs          | 32 ++++++++++++++++---
 1 file changed, 27 insertions(+), 5 deletions(-)

diff --git a/src/interpreter/instructions/lowering_lifting.rs b/src/interpreter/instructions/lowering_lifting.rs
index cd43104..1ba8a38 100644
--- a/src/interpreter/instructions/lowering_lifting.rs
+++ b/src/interpreter/instructions/lowering_lifting.rs
@@ -23,11 +23,17 @@ macro_rules! lowering_lifting {
                                 )?))
                         }
 
-                        Some(_) => {
-                            return Err(concat!(
-                                "Instruction `",
-                                $instruction_name,
-                                "` expects a `i32` value on the stack."
+                        Some(wrong_value) => {
+                            return Err(format!(
+                                concat!(
+                                    "Instruction `",
+                                    $instruction_name,
+                                    "` expects a `",
+                                    stringify!($from_variant),
+                                    "` value on the stack, got `{:?}`.",
+                                ),
+                                wrong_value
+
                             )
                             .to_string())
                         },
@@ -92,6 +98,22 @@ mod tests {
             stack: [InterfaceValue::S8(42)],
     );
 
+    test_executable_instruction!(
+        test_type_mismatch =
+            instructions: [Instruction::ArgumentGet { index: 0}, Instruction::I32ToS8],
+            invocation_inputs: [InterfaceValue::I64(42)],
+            instance: Instance::new(),
+            error: "Instruction `i32-to-s8` expects a `I32` value on the stack, got `I64(42)`."
+    );
+
+    test_executable_instruction!(
+        test_no_value_on_the_stack =
+            instructions: [Instruction::I32ToS8],
+            invocation_inputs: [InterfaceValue::I32(42)],
+            instance: Instance::new(),
+            error: "Instruction `i32-to-s8` needs one value on the stack."
+    );
+
     test_executable_instruction!(
         test_i32_to_u8 =
             instructions: [Instruction::ArgumentGet { index: 0 }, Instruction::I32ToU8],