Add assertThrows-like test functionality

Author: marzipankaiser

examples/stdlib/test/exceptions.check

@@ -0,0 +1,17 @@
+Test test suite on Exceptions
+✓ Test test assertNotThrown pass
+✕ Test test assertNotThrown fail
+  Unexpected Exception
+✕ Test test assertThrown fail
+  Expected Exception, but exited normally
+✓ Test test assertThrows pass
+✓ Test test assertNoThrow pass
+✕ Test test assertNoThrow fail
+  Unexpected Exception
+✕ Test test assertThrows fail
+  Expected Exception, but exited normally
+✓ Test test assertThrows pass
+
+ 4 pass
+ 4 fail
+ 8 tests total

examples/stdlib/test/exceptions.effekt

@@ -0,0 +1,44 @@
+import test
+
+def main() = {
+  // Don't print out times in CI.
+  suite("Test test suite on Exceptions", false) {
+    // on[E] variant
+    // -------------
+    test("Test test assertNotThrown pass") {
+      with on[MissingValue].assertNotThrown
+      assert(Some(12).value, 12)
+    }
+    test("Test test assertNotThrown fail") {
+      with on[MissingValue].assertNotThrown
+      assert(None().value, 12)
+    }
+    test("Test test assertThrown fail") {
+      with on[MissingValue].assertThrown
+      assert(Some(12).value, 12)
+    }
+    test("Test test assertThrows pass") {
+      with on[MissingValue].assertThrown[MissingValue]
+      assert(None().value, 12)
+    }
+    // direct variant
+    // --------------
+    test("Test test assertNoThrow pass") {
+      with assertNoThrow[MissingValue]
+      assert(Some(12).value, 12)
+    }
+    test("Test test assertNoThrow fail") {
+      with assertNoThrow[MissingValue]
+      assert(None().value, 12)
+    }
+    test("Test test assertThrows fail") {
+      with assertThrows[MissingValue]
+      assert(Some(12).value, 12)
+    }
+    test("Test test assertThrows pass") {
+      with assertThrows[MissingValue]
+      assert(None().value, 12)
+    }
+  };
+  ()
+}

libraries/common/test.effekt

@@ -59,6 +59,18 @@ def assertEqual[A](obtained: A, expected: A) { equals: (A, A) => Bool } { show:
   // NOTE:                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   //             Here's an accidental capture! Can we prevent this somehow nicely?
 
+def assertNotThrown[E](ex: on[E]){ body: => Unit / Exception[E] }: Unit / Assertion = {
+  ex.default{ do assert(false, "Unexpected Exception") }{body}
+}
+def assertNoThrow[E]{ body: => Unit / Exception[E] }: Unit / Assertion = {
+  on[E].default{ do assert(false, "Unexpected Exception") }{body}
+}
+def assertThrown[E](ex: on[E]){ body: => Unit / Exception[E] }: Unit / Assertion = {
+  do assert(ex.default{ true }{ body(); false }, "Expected Exception, but exited normally")
+}
+def assertThrows[E]{body: => Unit / Exception[E] }: Unit / Assertion = {
+  do assert(on[E].default{ true }{ body(); false }, "Expected Exception, but exited normally")
+}
 
 interface Test {
   def success(name: String, duration: Int): Unit