[yew-devel] [PATCH yew-comp 05/20] rrd: units: add tests

[Dominik Csapak <d.csapak@proxmox.com>]

so we can argue about code changes more easily, also expand the range
check for negative ranges, since that should not happen.

this also adds some comments what the functions should do

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
---
 src/rrd/units.rs | 149 +++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 145 insertions(+), 4 deletions(-)

diff --git a/src/rrd/units.rs b/src/rrd/units.rs
index b29a238..ad72565 100644
--- a/src/rrd/units.rs
+++ b/src/rrd/units.rs
@@ -1,16 +1,21 @@
+// calculates the distance of the x axis labels + grid for base10 units
+// The distance calculated is always between 1/2 and 1/10 of the range
 pub(crate) fn get_grid_unit_base10(min: f64, max: f64) -> f64 {
     let range = max - min;
 
-    if range == 0.0 {
-        panic!("get_grid_unit_base10: got zero range - internal error");
+    if range <= 0.0 {
+        panic!("get_grid_unit_base10: got zero or negative range - internal error");
     }
 
     let mut l = range.log10() as i32;
 
+    // the count can be between 1 and 10
     while (range / 10.0_f64.powi(l)) < 2.0 {
         l -= 1;
     }
 
+    // now it must be between 2 and 20
+
     let mut res = 10.0_f64.powi(l);
 
     let count = range / res;
@@ -20,15 +25,18 @@ pub(crate) fn get_grid_unit_base10(min: f64, max: f64) -> f64 {
     } else if count > 10.0 {
         res *= 2.0;
     }
+    // here the count must be between 2 and 10
 
     res
 }
 
+// calculates the distance of the x axis labels + grid for base2 units
+// The distance calculated is always smaller than 1/4 of the range
 pub(crate) fn get_grid_unit_base2(min: f64, max: f64) -> f64 {
     let range = max - min;
 
-    if range == 0.0 {
-        panic!("get_grid_unit_base2: got zero range - internal error");
+    if range <= 0.0 {
+        panic!("get_grid_unit_base2: got zero or negative range - internal error");
     }
 
     let mut l = range.log2() as i32;
@@ -93,3 +101,136 @@ pub(crate) fn get_time_grid_unit(min: i64, max: i64) -> i64 {
 
     l
 }
+
+#[cfg(test)]
+mod test {
+    use std::panic;
+
+    use crate::rrd::units::get_time_grid_unit;
+
+    use super::{get_grid_unit_base10, get_grid_unit_base2};
+
+    const DELTA: f64 = 0.0000001;
+
+    #[test]
+    fn test_grid_unit_base2() {
+        // min, max, result
+        let test_data = [
+            // normal range tests
+            (0.0, 0.01, Some(2.0_f64.powi(-9))),
+            (0.0, 2.0, Some(2.0_f64.powi(-1))),
+            (0.0, 0.00001, Some(2.0_f64.powi(-19))),
+            (0.0, 100.0, Some(2.0_f64.powi(4))),
+            (0.0, 1_000_000.0, Some(2.0_f64.powi(17))),
+            (0.0, f64::MAX, Some(2.0_f64.powi(1021))),
+            (
+                10.0 * 1024.0 * 1024.0,
+                12.5 * 1024.0 * 1024.0,
+                Some(2.0_f64.powi(19)),
+            ),
+            // ranges with negative data
+            (-500.0, -100.0, Some(2.0_f64.powi(6))),
+            (-500.0, 100.0, Some(2.0_f64.powi(7))),
+            // panic tests
+            (0.0, 0.0, None),
+            (100.0, 0.01, None),
+        ];
+
+        for (min, max, expected) in test_data {
+            match (
+                panic::catch_unwind(|| get_grid_unit_base2(min, max)).ok(),
+                expected,
+            ) {
+                (Some(result), Some(expected)) => {
+                    let diff = result - expected;
+                    assert_eq!(
+                        diff < DELTA,
+                        diff > -DELTA,
+                        "{min} .. {max} ->\n {expected} \n {result}"
+                    )
+                }
+                (None, Some(expected)) => {
+                    panic!("panic'ed when it shouldn't: {min} .. {max} -> {expected}")
+                }
+                (Some(result), None) => {
+                    panic!("result when it should have panic'ed: {min} .. {max} -> {result}")
+                }
+                (None, None) => {}
+            }
+        }
+    }
+
+    #[test]
+    fn test_grid_unit_base10() {
+        // min, max, result
+        let test_data = [
+            // normal range tests
+            (0.0, 0.01, Some(0.001)),
+            (0.0, 2.0, Some(1.0)),
+            (0.0, 0.00001, Some(0.000002)),
+            (0.0, 100.0, Some(10.0)),
+            (0.0, 1_000_000.0, Some(100_000.0)),
+            (
+                0.0,
+                f64::MAX,
+                Some(5000000000000002.0 * 10.0_f64.powf(292.0)),
+            ),
+            (
+                10.0 * 1024.0 * 1024.0,
+                12.5 * 1024.0 * 1024.0,
+                Some(1_000_000.0),
+            ),
+            // ranges with negative data
+            (-500.0, -100.0, Some(100.0)),
+            (-500.0, 100.0, Some(100.0)),
+            // panic tests
+            (0.0, 0.0, None),
+            (100.0, 0.01, None),
+        ];
+
+        for (min, max, expected) in test_data {
+            match (
+                panic::catch_unwind(|| get_grid_unit_base10(min, max)).ok(),
+                expected,
+            ) {
+                (Some(result), Some(expected)) => {
+                    let diff = result - expected;
+                    assert_eq!(
+                        diff < DELTA,
+                        diff > -DELTA,
+                        "{min} .. {max} ->\n {expected} \n {result}"
+                    )
+                }
+                (None, Some(expected)) => {
+                    panic!("panic'ed when it shouldn't: {min} .. {max} -> {expected}")
+                }
+                (Some(result), None) => {
+                    panic!("result when it should have panic'ed: {min} .. {max} -> {result}")
+                }
+                (None, None) => {}
+            }
+        }
+    }
+
+    #[test]
+    fn test_time_grid_unit() {
+        // min max result
+        let test_data = [
+            (0, 10, 1),
+            (0, 100, 15),
+            (0, 1_000_000, 172800),
+            (0, i64::MAX, 1519964874237542400),
+            (-1000, 1_000_000, 172800),
+            (0, 0, 1),
+            (1, 0, 1),
+        ];
+
+        for (min, max, expected) in test_data {
+            assert_eq!(
+                get_time_grid_unit(min, max),
+                expected,
+                "{min}..{max} -> {expected}"
+            )
+        }
+    }
+}
-- 
2.39.5



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