test(sql): cover seedUsersForViews

src/test/kotlin/kestrel/store/sql/DiskExecutorTest.kt

@@ -2696,3 +2696,163 @@ class DiskExecutorTest {
         assertEquals(listOf(20L, 30L, 50L, 70L, 30L), result.rows.map { (it[1] as Value.IntegerValue).value })
     }
 
+    private fun Database.seedUsersForViews() {
+        run("CREATE TABLE users (id INTEGER PRIMARY KEY, name TEXT NOT NULL, age INTEGER, dept TEXT)")
+        run(
+            "INSERT INTO users VALUES " +
+                "(1, 'ada', 36, 'eng'), (2, 'linus', 54, 'eng'), (3, 'grace', 85, 'navy'), (4, 'alan', 41, NULL)"
+        )
+    }
+
+    @Test
+    fun createViewReturnsResultAndRegistersName() {
+        val db = newDatabase()
+        db.seedUsersForViews()
+        val result = db.run("CREATE VIEW adults AS SELECT id, name FROM users WHERE age >= 40").single()
+        assertEquals(CreateViewResult("adults"), result)
+        assertEquals(listOf("adults"), db.catalog.viewNames)
+    }
+
+    @Test
+    fun queryingAViewRunsItsDefiningQueryFresh() {
+        val db = newDatabase()
+        db.seedUsersForViews()
+        db.run("CREATE VIEW adults AS SELECT id, name FROM users WHERE age >= 40")
+        val first = db.select("SELECT name FROM adults ORDER BY id ASC")
+        assertEquals(listOf(text("linus"), text("grace"), text("alan")), first.rows.map { it.single() })
+
+        db.run("INSERT INTO users VALUES (5, 'margaret', 61, 'navy')")
+        val second = db.select("SELECT name FROM adults ORDER BY id ASC")
+        assertEquals(
+            listOf(text("linus"), text("grace"), text("alan"), text("margaret")),
+            second.rows.map { it.single() }
+        )
+    }
+
+    @Test
+    fun viewCanBeUsedAsAJoinTarget() {
+        val db = newDatabase()
+        db.seedUsersForViews()
+        db.run("CREATE TABLE bonuses (dept TEXT, amount INTEGER)")
+        db.run("INSERT INTO bonuses VALUES ('eng', 1000), ('navy', 500)")
+        db.run("CREATE VIEW eng_staff AS SELECT id, name, dept FROM users WHERE dept = 'eng'")
+        val result = db.select(
+            "SELECT eng_staff.name, bonuses.amount FROM eng_staff " +
+                "JOIN bonuses ON eng_staff.dept = bonuses.dept ORDER BY eng_staff.id ASC"
+        )
+        assertEquals(
+            listOf(listOf(text("ada"), int(1000)), listOf(text("linus"), int(1000))),
+            result.rows
+        )
+    }
+
+    @Test
+    fun viewOverAggregateQueryWorks() {
+        val db = newDatabase()
+        db.seedUsersForViews()
+        db.run("CREATE VIEW dept_counts AS SELECT dept, COUNT(*) AS n FROM users GROUP BY dept")
+        val result = db.select("SELECT dept, n FROM dept_counts WHERE n > 1 ORDER BY dept ASC")
+        assertEquals(listOf(listOf(text("eng"), int(2))), result.rows)
+    }
+
+    @Test
+    fun viewDefinitionCanReferenceAnotherView() {
+        val db = newDatabase()
+        db.seedUsersForViews()
+        db.run("CREATE VIEW adults AS SELECT id, name, age FROM users WHERE age >= 40")
+        db.run("CREATE VIEW seniors AS SELECT id, name FROM adults WHERE age >= 60")
+        val result = db.select("SELECT name FROM seniors")
+        assertEquals(listOf(listOf(text("grace"))), result.rows)
+    }
+
+    @Test
+    fun viewCanBeReferencedInsideAWithCteBody() {
+        val db = newDatabase()
+        db.seedUsersForViews()
+        db.run("CREATE VIEW adults AS SELECT id, name, age FROM users WHERE age >= 40")
+        val result = db.select("WITH a AS (SELECT name FROM adults WHERE age >= 60) SELECT name FROM a")
+        assertEquals(listOf(listOf(text("grace"))), result.rows)
+    }
+
+    @Test
+    fun viewCanAppearOnEitherSideOfASetOperation() {
+        val db = newDatabase()
+        db.seedUsersForViews()
+        db.run("CREATE VIEW eng AS SELECT name FROM users WHERE dept = 'eng'")
+        db.run("CREATE VIEW navy AS SELECT name FROM users WHERE dept = 'navy'")
+        val result = db.select("SELECT name FROM eng UNION SELECT name FROM navy ORDER BY name")
+        assertEquals(listOf(listOf(text("ada")), listOf(text("grace")), listOf(text("linus"))), result.rows)
+    }
+
+    @Test
+    fun creatingAViewValidatesColumnsEagerly() {
+        val db = newDatabase()
+        db.seedUsersForViews()
+        assertFailsWith<KestrelException> { db.run("CREATE VIEW broken AS SELECT nope FROM users") }
+        assertTrue(db.catalog.viewNames.isEmpty())
+    }
+
+    @Test
+    fun creatingAViewOverAnUnknownTableFails() {
+        val db = newDatabase()
+        assertFailsWith<KestrelException> { db.run("CREATE VIEW v AS SELECT * FROM missing") }
+    }
+
+    @Test
+    fun duplicateViewNameFailsWithoutOrReplace() {
+        val db = newDatabase()
+        db.seedUsersForViews()
+        db.run("CREATE VIEW adults AS SELECT id FROM users WHERE age >= 18")
+        assertFailsWith<KestrelException> { db.run("CREATE VIEW adults AS SELECT id FROM users WHERE age >= 21") }
+    }
+
+    @Test
+    fun createOrReplaceViewSwapsTheDefinition() {
+        val db = newDatabase()
+        db.seedUsersForViews()
+        db.run("CREATE VIEW adults AS SELECT id FROM users WHERE age >= 18")
+        db.run("CREATE OR REPLACE VIEW adults AS SELECT id FROM users WHERE age >= 50")
+        val result = db.select("SELECT id FROM adults ORDER BY id ASC")
+        assertEquals(listOf(listOf(int(2)), listOf(int(3))), result.rows)
+    }
+
+    @Test
+    fun dropViewRemovesItAndItStopsBeingQueryable() {
+        val db = newDatabase()
+        db.seedUsersForViews()
+        db.run("CREATE VIEW adults AS SELECT id FROM users WHERE age >= 18")
+        val result = db.run("DROP VIEW adults").single()
+        assertEquals(DropViewResult("adults"), result)
+        assertFailsWith<KestrelException> { db.run("SELECT * FROM adults") }
+    }
+
+    @Test
+    fun droppingAnUnknownViewFails() {
+        val db = newDatabase()
+        assertFailsWith<DiskCatalogException> { db.run("DROP VIEW nope") }
+    }
+
+    @Test
+    fun cannotCreateTableWithSameNameAsAnExistingView() {
+        val db = newDatabase()
+        db.seedUsersForViews()
+        db.run("CREATE VIEW adults AS SELECT id FROM users WHERE age >= 18")
+        assertFailsWith<DiskCatalogException> { db.run("CREATE TABLE adults (id INTEGER)") }
+    }
+
+    @Test
+    fun cannotCreateViewWithSameNameAsAnExistingTable() {
+        val db = newDatabase()
+        db.seedUsersForViews()
+        assertFailsWith<DiskCatalogException> { db.run("CREATE VIEW users AS SELECT id FROM users") }
+    }
+
+    @Test
+    fun dropTableRefusesAViewNameAndDropViewRefusesATableName() {
+        val db = newDatabase()
+        db.seedUsersForViews()
+        db.run("CREATE VIEW adults AS SELECT id FROM users WHERE age >= 18")
+        assertFailsWith<DiskCatalogException> { db.run("DROP TABLE adults") }
+        assertFailsWith<DiskCatalogException> { db.run("DROP VIEW users") }
+    }
+