diff --git a/extras/beast/test/fail_counter.hpp b/extras/beast/test/fail_counter.hpp
index e263a31a..4ad34959 100644
--- a/extras/beast/test/fail_counter.hpp
+++ b/extras/beast/test/fail_counter.hpp
@@ -83,6 +83,26 @@ make_error_code(error ev)
             detail::get_error_category()};
 }
 
+/** An error code with an error set on default construction
+
+    Default constructed versions of this object will have
+    an error code set right away. This helps tests find code
+    which forgets to clear the error code on success.
+*/
+struct fail_error_code : error_code
+{
+    fail_error_code()
+        : error_code(make_error_code(error::fail_error))
+    {
+    }
+
+    template<class Arg0, class... ArgN>
+    fail_error_code(Arg0&& arg0, ArgN&&... argn)
+        : error_code(arg0, std::forward<ArgN>(argn)...)
+    {
+    }
+};
+
 /** A countdown to simulated failure.
 
     On the Nth operation, the class will fail with the specified
diff --git a/test/core/buffered_read_stream.cpp b/test/core/buffered_read_stream.cpp
index e4338814..81536e1e 100644
--- a/test/core/buffered_read_stream.cpp
+++ b/test/core/buffered_read_stream.cpp
@@ -59,7 +59,7 @@ public:
                 decltype(fs)&, multi_buffer> srs(fs);
             srs.buffer().commit(buffer_copy(
                 srs.buffer().prepare(5), buffer("Hello", 5)));
-            error_code ec;
+            error_code ec = test::error::fail_error;
             boost::asio::read(srs, buffer(&s[0], s.size()), ec);
             if(! ec)
             {
@@ -78,7 +78,7 @@ public:
             srs.capacity(3);
             srs.buffer().commit(buffer_copy(
                 srs.buffer().prepare(5), buffer("Hello", 5)));
-            error_code ec;
+            error_code ec = test::error::fail_error;
             boost::asio::read(srs, buffer(&s[0], s.size()), ec);
             if(! ec)
             {
@@ -96,7 +96,7 @@ public:
                 decltype(fs)&, multi_buffer> srs(fs);
             srs.buffer().commit(buffer_copy(
                 srs.buffer().prepare(5), buffer("Hello", 5)));
-            error_code ec;
+            error_code ec = test::error::fail_error;
             boost::asio::async_read(
                 srs, buffer(&s[0], s.size()), do_yield[ec]);
             if(! ec)
@@ -116,7 +116,7 @@ public:
             srs.capacity(3);
             srs.buffer().commit(buffer_copy(
                 srs.buffer().prepare(5), buffer("Hello", 5)));
-            error_code ec;
+            error_code ec = test::error::fail_error;
             boost::asio::async_read(
                 srs, buffer(&s[0], s.size()), do_yield[ec]);
             if(! ec)
diff --git a/test/http/read.cpp b/test/http/read.cpp
index 937b522c..3e28ea50 100644
--- a/test/http/read.cpp
+++ b/test/http/read.cpp
@@ -50,7 +50,7 @@ public:
             test::fail_stream<
                 test::string_istream> fs{fc, ios_, ""};
             test_parser<isRequest> p(fc);
-            error_code ec;
+            error_code ec = test::error::fail_error;
             read(fs, b, p, ec);
             if(! ec)
                 break;
@@ -66,7 +66,7 @@ public:
             test::fail_stream<test::string_istream> fs{
                 fc, ios_, std::string{s + pre, len - pre}};
             test_parser<isRequest> p(fc);
-            error_code ec;
+            error_code ec = test::error::fail_error;
             read(fs, b, p, ec);
             if(! ec)
                 break;
@@ -81,7 +81,7 @@ public:
             test::fail_stream<
                 test::string_istream> fs{fc, ios_, ""};
             test_parser<isRequest> p(fc);
-            error_code ec;
+            error_code ec = test::error::fail_error;
             async_read(fs, b, p, do_yield[ec]);
             if(! ec)
                 break;
@@ -97,7 +97,7 @@ public:
             test::fail_stream<test::string_istream> fs{
                 fc, ios_, std::string{s + pre, len - pre}};
             test_parser<isRequest> p(fc);
-            error_code ec;
+            error_code ec = test::error::fail_error;
             async_read(fs, b, p, do_yield[ec]);
             if(! ec)
                 break;
@@ -158,7 +158,7 @@ public:
                 "10\r\n"
                 "****************\r\n"
                 "0\r\n\r\n";
-            error_code ec;
+            error_code ec = test::error::fail_error;
             static_buffer_n<10> b;
             request<string_body> req;
             read(p.server, b, req, ec);
@@ -266,7 +266,7 @@ public:
                 "\r\n"
             );
             request<dynamic_body> m;
-            error_code ec;
+            error_code ec = test::error::fail_error;
             multi_buffer b;
             read(fs, b, m, ec);
             if(! ec)
@@ -284,7 +284,7 @@ public:
                 "\r\n"
             );
             request<dynamic_body> m;
-            error_code ec;
+            error_code ec = test::error::fail_error;
             multi_buffer b;
             async_read(fs, b, m, do_yield[ec]);
             if(! ec)
@@ -393,7 +393,7 @@ public:
         for(std::size_t n = 1; n < s.size() - 1; ++n)
         {
             Parser p;
-            error_code ec;
+            error_code ec = test::error::fail_error;
             flat_buffer b;
             test::pipe c{ios_};
             ostream(c.server.buffer) << s;
@@ -442,7 +442,6 @@ public:
     void
     run() override
     {
-#if 0
         testThrow();
         testBufferOverflow();
 
@@ -455,7 +454,6 @@ public:
 
         testIoService();
         testRegression430();
-#endif
         testReadGrind();
     }
 };
diff --git a/test/http/write.cpp b/test/http/write.cpp
index 3d8d6db9..d3d9895c 100644
--- a/test/http/write.cpp
+++ b/test/http/write.cpp
@@ -395,7 +395,7 @@ public:
             m.insert(field::user_agent, "test");
             m.insert("Transfer-Encoding", "chunked");
             m.body = "*****";
-            error_code ec;
+            error_code ec = test::error::fail_error;
             write(fs, m, ec);
             if(ec == error::end_of_stream)
             {
@@ -428,7 +428,7 @@ public:
             m.insert(field::user_agent, "test");
             m.insert("Transfer-Encoding", "chunked");
             m.body = "*****";
-            error_code ec;
+            error_code ec = test::error::fail_error;
             async_write(fs, m, do_yield[ec]);
             if(ec == error::end_of_stream)
             {
@@ -461,7 +461,7 @@ public:
             m.insert(field::user_agent, "test");
             m.insert("Content-Length", "5");
             m.body = "*****";
-            error_code ec;
+            error_code ec = test::error::fail_error;
             write(fs, m, ec);
             if(! ec)
             {
@@ -489,7 +489,7 @@ public:
             m.insert(field::user_agent, "test");
             m.insert("Content-Length", "5");
             m.body = "*****";
-            error_code ec;
+            error_code ec = test::error::fail_error;
             async_write(fs, m, do_yield[ec]);
             if(! ec)
             {
diff --git a/test/websocket/stream.cpp b/test/websocket/stream.cpp
index 45747d7c..91f06a7a 100644
--- a/test/websocket/stream.cpp
+++ b/test/websocket/stream.cpp
@@ -965,7 +965,7 @@ public:
     void
     testHandshake()
     {
-        error_code ec;
+        error_code ec = test::error::fail_error;
         ::websocket::async_echo_server server{nullptr, 1};
         auto const any = endpoint_type{
             address_type::from_string("127.0.0.1"), 0};
@@ -1177,7 +1177,7 @@ public:
             std::vector<char> v;
             for(char n = 0; n < 20; ++n)
             {
-                error_code ec;
+                error_code ec = test::error::fail_error;
                 socket_type sock(ios_);
                 sock.connect(ep, ec);
                 if(! BEAST_EXPECTS(! ec, ec.message()))
@@ -1202,7 +1202,7 @@ public:
             std::vector<char> v;
             for(char n = 0; n < 20; ++n)
             {
-                error_code ec;
+                error_code ec = test::error::fail_error;
                 socket_type sock(ios_);
                 sock.connect(ep, ec);
                 if(! BEAST_EXPECTS(! ec, ec.message()))