Fix crash when unhandled exception is cleared by teardown

asynctest/templates.nim

@@ -20,8 +20,10 @@ template suite*(name, body) =
 
     template teardown(teardownBody) {.used.} =
       teardown:
+        let exception = getCurrentException()
         let asyncproc = proc {.async.} = teardownBody
         waitFor asyncproc()
+        setCurrentException(exception)
 
     let suiteproc = proc = # Avoids GcUnsafe2 warnings with chronos
       body

testmodules/chronos/test.nim

@@ -2,3 +2,4 @@ import pkg/asynctest
 import pkg/chronos
 
 include ../stdlib/testbody
+include ../stdlib/testfail

testmodules/stdlib/test.nim

@@ -2,3 +2,4 @@ import std/asyncdispatch
 import pkg/asynctest
 
 include ./testbody
+include ./testfail

testmodules/stdlib/testfail.nim

@@ -0,0 +1,28 @@
+import std/exitprocs
+
+template silent(body) =
+
+  let exitcode = getProgramResult()
+  resetOutputFormatters()
+  addOutputFormatter(OutputFormatter())
+
+  body
+
+  resetOutputFormatters()
+  addOutputFormatter(defaultConsoleFormatter())
+  setProgramResult(exitcode)
+
+suite "reports unhandled exception when teardown handles exceptions too":
+
+  silent:
+
+    proc someAsyncProc {.async.} = discard
+
+    teardown:
+      try:
+        await someAsyncProc()
+      except:
+        discard
+
+    test "should fail, but not crash":
+      raise newException(ValueError, "This exception is expected")

testmodules/unittest2/test.nim

@@ -2,3 +2,4 @@ import pkg/asynctest/unittest2
 import pkg/chronos
 
 include ../stdlib/testbody
+include ../stdlib/testfail