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use std::collections::HashMap;
use cupel::{
ChronologicalPlacer, ContextBudget, ContextItemBuilder, GreedySlice, ItemStatus,
OverflowStrategy, Pipeline, PriorityScorer, ReflexiveScorer, policy_sensitivity_from_pipelines,
};
/// Build a pipeline using `ReflexiveScorer` (passes through `future_relevance_hint`
/// as the score) with the given overflow strategy.
fn reflexive_pipeline(overflow: OverflowStrategy) -> Pipeline {
Pipeline::builder()
.scorer(Box::new(ReflexiveScorer))
.slicer(Box::new(GreedySlice))
.placer(Box::new(ChronologicalPlacer))
.overflow_strategy(overflow)
.build()
.unwrap()
}
/// Build a pipeline using `PriorityScorer` so items with higher priority sort
/// first; combined with a tight budget this excludes low-priority items.
fn priority_pipeline(overflow: OverflowStrategy) -> Pipeline {
Pipeline::builder()
.scorer(Box::new(PriorityScorer))
.slicer(Box::new(GreedySlice))
.placer(Box::new(ChronologicalPlacer))
.overflow_strategy(overflow)
.build()
.unwrap()
}
#[test]
fn policy_sensitivity_two_variants_produces_diff() {
// Create items with varying tokens and priority/relevance.
// The tight budget (100 tokens) will force exclusion of some items.
let items = vec![
ContextItemBuilder::new("important-item", 40)
.future_relevance_hint(0.9)
.priority(10)
.build()
.unwrap(),
ContextItemBuilder::new("medium-item", 40)
.future_relevance_hint(0.5)
.priority(5)
.build()
.unwrap(),
ContextItemBuilder::new("low-item", 40)
.future_relevance_hint(0.1)
.priority(1)
.build()
.unwrap(),
];
// Tight budget: only ~2 of 3 items fit (100 tokens, items are 40 each).
let tight_budget = ContextBudget::new(100, 80, 0, HashMap::new(), 0.0).unwrap();
// Variant A: tight budget with reflexive scorer (scores by future_relevance_hint).
let pipeline_a = reflexive_pipeline(OverflowStrategy::Throw);
// Variant B: tight budget with priority scorer — different ranking yields different inclusions.
let pipeline_b = priority_pipeline(OverflowStrategy::Throw);
let variants: Vec<(&str, &Pipeline)> =
vec![("reflexive", &pipeline_a), ("priority", &pipeline_b)];
let report = policy_sensitivity_from_pipelines(&items, &tight_budget, &variants).unwrap();
// Both variants should be present.
assert_eq!(report.variants.len(), 2);
assert_eq!(report.variants[0].0, "reflexive");
assert_eq!(report.variants[1].0, "priority");
// With the tight budget (100 tokens) and 3 items of 40 tokens each,
// each pipeline can include at most 2 items. The different scorers
// should rank items differently, causing at least one item to differ.
//
// ReflexiveScorer uses future_relevance_hint: 0.9, 0.5, 0.1
// PriorityScorer uses priority: 10, 5, 1
// Both rank the same order in this case, so let's verify the reports
// and check for diffs. If both agree, adjust the test.
// Check each variant's included count.
let included_a: Vec<&str> = report.variants[0]
.1
.included
.iter()
.map(|i| i.item.content())
.collect();
let included_b: Vec<&str> = report.variants[1]
.1
.included
.iter()
.map(|i| i.item.content())
.collect();
// Both should include exactly 2 items (80 tokens of budget with 40-token items).
assert_eq!(
included_a.len(),
2,
"variant A should include 2 items, got: {included_a:?}"
);
assert_eq!(
included_b.len(),
2,
"variant B should include 2 items, got: {included_b:?}"
);
// If the scorers produce different rankings, there will be diffs.
// If they agree (both exclude "low-item"), diffs will be empty.
// Let's handle both cases: the important thing is the function works.
// We'll create a second test that guarantees a diff.
}
#[test]
fn policy_sensitivity_guaranteed_diff() {
// Use a budget that can only fit ONE item to guarantee different selections
// with different scorers.
let items = vec![
ContextItemBuilder::new("high-relevance-low-priority", 40)
.future_relevance_hint(0.9)
.priority(1) // low priority
.build()
.unwrap(),
ContextItemBuilder::new("low-relevance-high-priority", 40)
.future_relevance_hint(0.1)
.priority(10) // high priority
.build()
.unwrap(),
];
// Budget fits exactly 1 item.
let budget = ContextBudget::new(50, 40, 0, HashMap::new(), 0.0).unwrap();
let pipeline_reflexive = reflexive_pipeline(OverflowStrategy::Throw);
let pipeline_priority = priority_pipeline(OverflowStrategy::Throw);
let variants: Vec<(&str, &Pipeline)> = vec![
("reflexive", &pipeline_reflexive),
("priority", &pipeline_priority),
];
let report = policy_sensitivity_from_pipelines(&items, &budget, &variants).unwrap();
assert_eq!(report.variants.len(), 2);
assert_eq!(report.variants[0].0, "reflexive");
assert_eq!(report.variants[1].0, "priority");
// ReflexiveScorer: picks "high-relevance-low-priority" (score 0.9)
// PriorityScorer: picks "low-relevance-high-priority" (score from priority 10)
// So both items should appear in the diff.
assert!(
!report.diffs.is_empty(),
"expected at least one diff entry, got none"
);
// Both items should be in the diff since they swap status.
assert_eq!(
report.diffs.len(),
2,
"expected 2 diff entries (both items swap), got {}",
report.diffs.len()
);
// Verify each diff entry has exactly 2 statuses with opposing values.
for entry in &report.diffs {
assert_eq!(
entry.statuses.len(),
2,
"expected 2 statuses per diff entry for content '{}', got {}",
entry.content,
entry.statuses.len()
);
let status_values: Vec<ItemStatus> = entry.statuses.iter().map(|(_, s)| *s).collect();
assert!(
status_values.contains(&ItemStatus::Included)
&& status_values.contains(&ItemStatus::Excluded),
"expected one Included and one Excluded for content '{}', got {:?}",
entry.content,
status_values
);
}
}