test(promql): keep Go float format tests with go_format and pin histogram_quantiles constants

Signed-off-by: Dennis Zhuang <killme2008@gmail.com>

src/promql/src/aggregate/tests.rs

@@ -898,28 +898,6 @@ fn an_aggregation_of_sparse_inputs_is_compared_in_full_against_the_reference() {
     assert_eq!(piece_ranges(&counts), vec![(2, 1), (6, 1)]);
 }
 
-/// `count_values` writes value labels the way Go's `strconv.FormatFloat(v, 'f', -1, 64)` does,
-/// including the round-half-even choice of the last shortest digit; see the header of
-/// `format_float_cases.txt` (promql-compat `cmd/narthex-golden-formatfloat`).
-#[test]
-fn value_labels_format_like_go() {
-    let mut checked = 0;
-    for line in include_str!("format_float_cases.txt").lines() {
-        let (bits, expected) = line.split_once(' ').unwrap();
-        let value = f64::from_bits(u64::from_str_radix(bits, 16).unwrap());
-        assert_eq!(crate::go_format::format_float_f(value), expected, "{bits}");
-        checked += 1;
-    }
-    assert!(checked > 2_400, "{checked}");
-    for (value, expected) in [
-        (f64::NAN, "NaN"),
-        (f64::INFINITY, "+Inf"),
-        (f64::NEG_INFINITY, "-Inf"),
-    ] {
-        assert_eq!(crate::go_format::format_float_f(value), expected);
-    }
-}
-
 /// A point where the `q` scalar has no value has no `quantile` result, as a missing scalar point
 /// yields no output in the other scalar operators.
 #[test]

src/promql/src/go_format/tests.rs

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use crate::go_format::format_open_metrics_float;
+use crate::go_format::{format_float_f, format_open_metrics_float};
 
 /// Prometheus `labels.FormatOpenMetricsFloat`; `open_metrics_cases.txt` comes from promql-compat
 /// `narthex-golden-formatfloat -openmetrics` as `<hex bits> <formatted>`.
@@ -27,3 +27,25 @@ fn open_metrics_floats_format_like_prometheus() {
     }
     assert!(checked > 300, "{checked}");
 }
+
+/// Go's `strconv.FormatFloat(v, 'f', -1, 64)`, the form `count_values` writes value labels in,
+/// including the round-half-even choice of the last shortest digit and the round-trip check at
+/// powers of two; `float_cases.txt` comes from promql-compat `narthex-golden-formatfloat`.
+#[test]
+fn floats_format_like_go() {
+    let mut checked = 0;
+    for line in include_str!("float_cases.txt").lines() {
+        let (bits, expected) = line.split_once(' ').unwrap();
+        let value = f64::from_bits(u64::from_str_radix(bits, 16).unwrap());
+        assert_eq!(format_float_f(value), expected, "{bits}");
+        checked += 1;
+    }
+    assert!(checked > 2_400, "{checked}");
+    for (value, expected) in [
+        (f64::NAN, "NaN"),
+        (f64::INFINITY, "+Inf"),
+        (f64::NEG_INFINITY, "-Inf"),
+    ] {
+        assert_eq!(format_float_f(value), expected);
+    }
+}

src/promql/src/histogram_eval.rs

@@ -62,6 +62,9 @@ pub enum HistogramFunction {
 /// writes it. Results that then share a label set merge as [`merge_same_labelset`] does, so a
 /// repeated `q`, or a `label` that overwrites the label telling two histograms apart, fails at a
 /// point both hold.
+///
+/// Each `q` is a constant. Prometheus evaluates the quantile arguments at every step, so a
+/// quantile that varies over time is not this kernel's to evaluate.
 pub fn histogram_quantiles(
     label: &str,
     quantiles: &[f64],

src/promql/src/histogram_eval/tests.rs

@@ -151,7 +151,7 @@ fn histogram_quantiles_match_prometheus() {
         let actual = histogram_quantiles(&case.spec[1], &quantiles, &schema, &input);
         failed += usize::from(assert_outcome(case, actual, &case.outcome));
     }
-    assert!(failed > 5, "{failed} failed");
+    assert_eq!(failed, 13, "{failed} failed");
 }
 
 #[test]