E0079: mock_target

E0079 mock_target — a mock naming no handler.

A compile-time error of soma check, the checker of the Soma programming language (soma explain E0079).

The rule

A mock line in a test must name a handler or a builtin that the program can call; a mock naming nothing would never fire, and the test would pass without the mock ever being used. Fix the name so that it matches the handler (here mock price_of 250).

A program that triggers it

cell Checkout {
    on price_of(sku: String) {
        return 100
    }
    on total(sku: String, qty: Int) {
        return price_of(sku) * qty
    }
}

cell test CheckoutTests {
    rules {
        mock price 250
        assert total("book", 2) == 500
    }
}

What soma check prints:

$ soma check wrong.cell
error: `mock price`: no handler or builtin named `price` — this mock would never fire
  --> wrong.cell:12:9
   |
12 |         mock price 250
   |         ^
  = code: E0079
✗ 1 error(s), 0 warning(s).

The fix field of soma check --json: this mock would never fire

The fix

On line 12, mock price 250 becomes mock price_of 250.

--- wrong.cell
+++ right.cell
@@ -10,5 +10,5 @@
 cell test CheckoutTests {
     rules {
-        mock price 250
+        mock price_of 250
         assert total("book", 2) == 500
     }

With the fix, soma check accepts the program:

$ soma check right.cell
✓ All checks passed.