native test framework

README.md

@@ -73,6 +73,27 @@ linker inputs) and, like those flags, their paths are relative to the invocation
 directory. Lists take the address of an array literal; empty lists are written
 `&[]`. See `examples/build/` for runnable projects.
 
+Projects can declare tests directly and run them with `brolang test [root]`.
+The command reads the same `build.bro`, writes `build/<name>-test`, and reuses
+its C link inputs, libraries, include paths, and defines.
+
+```bro
+math :: import "../math"
+testing :: import "@std/testing"
+
+test import "../math"
+
+addition test {
+	try testing.expect(math.add(20, 22) == 42)
+	try testing.expect_equal(42, math.add(20, 22))
+}
+```
+
+`test import` discovers tests transitively without creating a namespace;
+calling package code still requires an ordinary import. Ordinary imports do
+not discover dependency tests. Assertions report their source location, a
+failure ends only the current test, and the runner continues with the suite.
+
 Relative `.h` imports create synthetic package namespaces backed by libclang:
 
 ```bro