.

canbench-bin/tests/tests.rs

@@ -39,7 +39,7 @@ Benchmark: no_changes_test
 
 ---------------------------------------------------
 
-Executed 1 of 4 benchmarks.
+Executed 1 of 5 benchmarks.
 "
             );
         });
@@ -61,7 +61,7 @@ Benchmark: noisy_change_test
 
 ---------------------------------------------------
 
-Executed 1 of 4 benchmarks.
+Executed 1 of 5 benchmarks.
 "
             );
         });
@@ -84,7 +84,7 @@ Benchmark: regression_test
 
 ---------------------------------------------------
 
-Executed 1 of 4 benchmarks.
+Executed 1 of 5 benchmarks.
 "
             );
         });
@@ -106,7 +106,29 @@ Benchmark: improvement_test
 
 ---------------------------------------------------
 
-Executed 1 of 4 benchmarks.
+Executed 1 of 5 benchmarks.
+"
+            );
+        });
+}
+
+#[test]
+fn benchmark_reports_regression_from_zero() {
+    BenchTest::canister("measurements_output")
+        .with_bench("stable_memory_increase")
+        .run(|output| {
+            assert_success!(
+                output,
+                "
+---------------------------------------------------
+
+Benchmark: stable_memory_increase
+  instructions: 404 (regressed from 0)
+  stable_memory_size: 123 (regressed from 0)
+
+---------------------------------------------------
+
+Executed 1 of 5 benchmarks.
 "
             );
         });

tests/measurements_output/canbench_results.yml

@@ -17,3 +17,8 @@ improvement_test:
   measurements:
     instructions: 3040
     stable_memory_size: 0
+
+stable_memory_increase:
+  measurements:
+    instructions: 0
+    stable_memory_size: 0

tests/measurements_output/src/main.rs

@@ -1,5 +1,10 @@
 use canbench::{benchmark, macros::bench, BenchResult};
 
+#[link(wasm_import_module = "ic0")]
+extern "C" {
+    pub fn stable64_grow(additional_pages: u64) -> i64;
+}
+
 // A benchmark that does nothing.
 // The values of the benchmark are persisted such that no change is reported.
 #[bench]
@@ -28,4 +33,13 @@ fn improvement_test() -> BenchResult {
     benchmark(|| {})
 }
 
+// The values of the benchmark are persisted such that a regression from zero
+// is reported.
+#[bench]
+fn stable_memory_increase() -> BenchResult {
+    benchmark(|| {
+        unsafe { stable64_grow(123) }
+    })
+}
+
 fn main() {}