add additional Result constructor checks

Author: liam-teale

tests/result.cpp

@@ -1,9 +1,16 @@
 #include "common/result.hpp"
 
+#include <string>
+
 // there'll be a lot of unused variables, since we just want to see if it compiles
 #pragma GCC diagnostic ignored "-Wunused-variable"
 
-class MyError {};
+class MyError {
+  public:
+    constexpr MyError(std::string) {}
+
+    constexpr MyError() {}
+};
 
 class MyError2 {};
 
@@ -22,7 +29,17 @@ zest::Result<int, MyError> test_function_2() {
 }
 
 constexpr void compile_time_tests() {
-    // test sentinel values
+    {
+        // check constructors
+        zest::Result<int, MyError> a(MyError{});
+        zest::Result<int, MyError> b("test_MyError_conversion");
+        zest::Result<int, MyError> c(2);
+        zest::Result<int, MyError> d(2.0);
+        zest::Result<int, MyError> e;
+        zest::Result<void, MyError> f(MyError{});
+        zest::Result<void, MyError> g("test_MyError_conversion");
+    }
+
     {
         // test comparison operator
         static_assert(zest::Result<int, MyError>(2) == zest::Result<int, MyError>(2));
@@ -42,10 +59,6 @@ constexpr void compile_time_tests() {
         const int&& e = zest::Result<int, MyError>(2);
         int f = a;
     }
-
-    {
-        // test error getting
-    }
 }
 
 void runtime_tests() {}