Add method to run the compressor starting from a particular compressor-state (#55)

compressor_integration_tests/tests/compressor_continue_run_tests.rs

@@ -0,0 +1,82 @@
+use compressor_integration_tests::{
+    add_contents_to_database, database_collapsed_states_match_map, database_structure_matches_map,
+    empty_database,
+    map_builder::{compressed_3_3_from_0_to_13_with_state, line_segments_with_state},
+    DB_URL,
+};
+use serial_test::serial;
+use synapse_compress_state::{continue_run, Level};
+
+// Tests the saving and continuing functionality
+// The compressor should produce the same results when run in one go
+// as when run in multiple stages
+#[test]
+#[serial(db)]
+fn continue_run_called_twice_same_as_run() {
+    // This starts with the following structure
+    //
+    // 0-1-2 3-4-5 6-7-8 9-10-11 12-13
+    //
+    // Each group i has state:
+    //     ('node','is',      i)
+    //     ('group',  j, 'seen') - for all j less than i
+    let initial = line_segments_with_state(0, 13);
+
+    // Place this initial state into an empty database
+    empty_database();
+    add_contents_to_database("room1", &initial);
+
+    let db_url = DB_URL.to_string();
+    let room_id = "room1".to_string();
+
+    // will run the compression in two batches
+    let start = -1;
+    let chunk_size = 7;
+
+    // compress in 3,3 level sizes
+    // since the compressor hasn't been run before they are empty
+    let level_info = vec![Level::restore(3, 0, None), Level::restore(3, 0, None)];
+
+    // Run the compressor with those settings
+    let chunk_stats_1 = continue_run(start, chunk_size, &db_url, &room_id, &level_info);
+
+    // Assert that it stopped at 6 (i.e. after the 7 groups 0...6)
+    assert_eq!(chunk_stats_1.last_compressed_group, 6);
+    // structure should be the following at this point
+    // (NOTE: only including compressed groups)
+    //
+    // 0  3\
+    // 1  4 6
+    // 2  5
+    assert_eq!(
+        chunk_stats_1.new_level_info,
+        vec![Level::restore(3, 1, Some(6)), Level::restore(3, 2, Some(6))]
+    );
+
+    let start = 6;
+    let chunk_size = 7;
+    let level_info = chunk_stats_1.new_level_info.clone();
+
+    // Run the compressor with those settings
+    let chunk_stats_2 = continue_run(start, chunk_size, &db_url, &room_id, &level_info);
+
+    // Assert that it stopped at 7
+    assert_eq!(chunk_stats_2.last_compressed_group, 13);
+
+    // This should have created the following structure in the database
+    // i.e. groups 6 and 9 should have changed from before
+    // N.B. this saves 11 rows
+    //
+    // 0  3\      12
+    // 1  4 6\    13
+    // 2  5 7 9
+    //      8 10
+    //        11
+    let expected = compressed_3_3_from_0_to_13_with_state();
+
+    // Check that the database still gives correct states for each group!
+    assert!(database_collapsed_states_match_map(&initial));
+
+    // Check that the structure of the database matches the expected structure
+    assert!(database_structure_matches_map(&expected))
+}