Add more tests & rename 'Invalid' -> 'Unfinished'

examples/acceptance_tests/092/lib/foo.ak

@@ -0,0 +1,41 @@
+test foo_1() {
+  let a = {
+    let b = 42
+    b
+  }
+
+  a == 42
+}
+
+test foo_2() {
+  expect Some(a) = {
+    let b = 42
+    Some(b)
+  }
+
+  a == 42
+}
+
+test foo_3() {
+  let c = Some(42)
+
+  let a = {
+    expect Some(b) = c
+    b
+  }
+
+  a == 42
+}
+
+test foo_4() {
+  let a = {
+    let b = 2
+    let c = {
+      let d = 14
+      d * b
+    }
+    c + 14
+  }
+
+  a == 42
+}