1 files changed, 195 insertions, 0 deletions
diff --git a/vendor/datafrog/src/test.rs b/vendor/datafrog/src/test.rs
new file mode 100644
index 000000000..9d5af3561
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+++ b/vendor/datafrog/src/test.rs
@@ -0,0 +1,195 @@
+#![cfg(test)]
+
+use crate::Iteration;
+use crate::Relation;
+use crate::RelationLeaper;
+use proptest::prelude::*;
+use proptest::{proptest, proptest_helper};
+
+fn inputs() -> impl Strategy<Value = Vec<(u32, u32)>> {
+    prop::collection::vec((0_u32..100, 0_u32..100), 1..500)
+}
+
+/// The original way to use datafrog -- computes reachable nodes from a set of edges
+fn reachable_with_var_join(edges: &[(u32, u32)]) -> Relation<(u32, u32)> {
+    let edges: Relation<_> = edges.iter().collect();
+    let mut iteration = Iteration::new();
+
+    let edges_by_successor = iteration.variable::<(u32, u32)>("edges_invert");
+    edges_by_successor.extend(edges.iter().map(|&(n1, n2)| (n2, n1)));
+
+    let reachable = iteration.variable::<(u32, u32)>("reachable");
+    reachable.insert(edges);
+
+    while iteration.changed() {
+        // reachable(N1, N3) :- edges(N1, N2), reachable(N2, N3).
+        reachable.from_join(&reachable, &edges_by_successor, |&_, &n3, &n1| (n1, n3));
+    }
+
+    reachable.complete()
+}
+
+/// Like `reachable`, but using a relation as an input to `from_join`
+fn reachable_with_relation_join(edges: &[(u32, u32)]) -> Relation<(u32, u32)> {
+    let edges: Relation<_> = edges.iter().collect();
+    let mut iteration = Iteration::new();
+
+    // NB. Changed from `reachable_with_var_join`:
+    let edges_by_successor: Relation<_> = edges.iter().map(|&(n1, n2)| (n2, n1)).collect();
+
+    let reachable = iteration.variable::<(u32, u32)>("reachable");
+    reachable.insert(edges);
+
+    while iteration.changed() {
+        // reachable(N1, N3) :- edges(N1, N2), reachable(N2, N3).
+        reachable.from_join(&reachable, &edges_by_successor, |&_, &n3, &n1| (n1, n3));
+    }
+
+    reachable.complete()
+}
+
+fn reachable_with_leapfrog(edges: &[(u32, u32)]) -> Relation<(u32, u32)> {
+    let edges: Relation<_> = edges.iter().collect();
+    let mut iteration = Iteration::new();
+
+    let edges_by_successor: Relation<_> = edges.iter().map(|&(n1, n2)| (n2, n1)).collect();
+
+    let reachable = iteration.variable::<(u32, u32)>("reachable");
+    reachable.insert(edges);
+
+    while iteration.changed() {
+        // reachable(N1, N3) :- edges(N1, N2), reachable(N2, N3).
+        reachable.from_leapjoin(
+            &reachable,
+            edges_by_successor.extend_with(|&(n2, _)| n2),
+            |&(_, n3), &n1| (n1, n3),
+        );
+    }
+
+    reachable.complete()
+}
+
+/// Computes a join where the values are summed -- uses iteration
+/// variables (the original datafrog technique).
+fn sum_join_via_var(
+    input1_slice: &[(u32, u32)],
+    input2_slice: &[(u32, u32)],
+) -> Relation<(u32, u32)> {
+    let mut iteration = Iteration::new();
+
+    let input1 = iteration.variable::<(u32, u32)>("input1");
+    input1.extend(input1_slice);
+
+    let input2 = iteration.variable::<(u32, u32)>("input1");
+    input2.extend(input2_slice);
+
+    let output = iteration.variable::<(u32, u32)>("output");
+
+    while iteration.changed() {
+        // output(K1, V1 * 100 + V2) :- input1(K1, V1), input2(K1, V2).
+        output.from_join(&input1, &input2, |&k1, &v1, &v2| (k1, v1 * 100 + v2));
+    }
+
+    output.complete()
+}
+
+/// Computes a join where the values are summed -- uses iteration
+/// variables (the original datafrog technique).
+fn sum_join_via_relation(
+    input1_slice: &[(u32, u32)],
+    input2_slice: &[(u32, u32)],
+) -> Relation<(u32, u32)> {
+    let input1: Relation<_> = input1_slice.iter().collect();
+    let input2: Relation<_> = input2_slice.iter().collect();
+    Relation::from_join(&input1, &input2, |&k1, &v1, &v2| (k1, v1 * 100 + v2))
+}
+
+proptest! {
+    #[test]
+    fn reachable_leapfrog_vs_var_join(edges in inputs()) {
+        let reachable1 = reachable_with_var_join(&edges);
+        let reachable2 = reachable_with_leapfrog(&edges);
+        assert_eq!(reachable1.elements, reachable2.elements);
+    }
+
+    #[test]
+    fn reachable_rel_join_vs_var_join(edges in inputs()) {
+        let reachable1 = reachable_with_var_join(&edges);
+        let reachable2 = reachable_with_relation_join(&edges);
+        assert_eq!(reachable1.elements, reachable2.elements);
+    }
+
+    #[test]
+    fn sum_join_from_var_vs_rel((set1, set2) in (inputs(), inputs())) {
+        let output1 = sum_join_via_var(&set1, &set2);
+        let output2 = sum_join_via_relation(&set1, &set2);
+        assert_eq!(output1.elements, output2.elements);
+    }
+
+    /// Test the behavior of `filter_anti` used on its own in a
+    /// leapjoin -- effectively it becomes an "intersection"
+    /// operation.
+    #[test]
+    fn filter_with_on_its_own((set1, set2) in (inputs(), inputs())) {
+        let input1: Relation<(u32, u32)> = set1.iter().collect();
+        let input2: Relation<(u32, u32)> = set2.iter().collect();
+        let intersection1 = Relation::from_leapjoin(
+            &input1,
+            input2.filter_with(|&tuple| tuple),
+            |&tuple, &()| tuple,
+        );
+
+        let intersection2: Relation<(u32, u32)> = input1.elements.iter()
+            .filter(|t| input2.elements.binary_search(&t).is_ok())
+            .collect();
+
+        assert_eq!(intersection1.elements, intersection2.elements);
+    }
+
+    /// Test the behavior of `filter_anti` used on its own in a
+    /// leapjoin -- effectively it becomes a "set minus" operation.
+    #[test]
+    fn filter_anti_on_its_own((set1, set2) in (inputs(), inputs())) {
+        let input1: Relation<(u32, u32)> = set1.iter().collect();
+        let input2: Relation<(u32, u32)> = set2.iter().collect();
+
+        let difference1 = Relation::from_leapjoin(
+            &input1,
+            input2.filter_anti(|&tuple| tuple),
+            |&tuple, &()| tuple,
+        );
+
+        let difference2: Relation<(u32, u32)> = input1.elements.iter()
+            .filter(|t| input2.elements.binary_search(&t).is_err())
+            .collect();
+
+        assert_eq!(difference1.elements, difference2.elements);
+    }
+}
+
+/// Test that `from_leapjoin` matches against the tuples from an
+/// `extend` that precedes first iteration.
+///
+/// This was always true, but wasn't immediately obvious to me until I
+/// re-read the code more carefully. -nikomatsakis
+#[test]
+fn leapjoin_from_extend() {
+    let doubles: Relation<(u32, u32)> = (0..10).map(|i| (i, i * 2)).collect();
+
+    let mut iteration = Iteration::new();
+
+    let variable = iteration.variable::<(u32, u32)>("variable");
+    variable.extend(Some((2, 2)));
+
+    while iteration.changed() {
+        variable.from_leapjoin(
+            &variable,
+            doubles.extend_with(|&(i, _)| i),
+            |&(i, _), &j| (i, j),
+        );
+    }
+
+    let variable = variable.complete();
+
+    assert_eq!(variable.elements, vec![(2, 2), (2, 4)]);
+}