diff --git a/src/groovy/src/test/groovy/solutions/bitbadger/documents/groovy/tests/integration/JsonDocument.groovy b/src/groovy/src/test/groovy/solutions/bitbadger/documents/groovy/tests/integration/JsonDocument.groovy
index 71594e8..db6c1bb 100644
--- a/src/groovy/src/test/groovy/solutions/bitbadger/documents/groovy/tests/integration/JsonDocument.groovy
+++ b/src/groovy/src/test/groovy/solutions/bitbadger/documents/groovy/tests/integration/JsonDocument.groovy
@@ -25,4 +25,19 @@ class JsonDocument {
     static void load(ThrowawayDatabase db, String tableName = TEST_TABLE) {
         testDocuments.forEach { db.conn.insert(tableName, it) }
     }
+
+    /** Document ID <code>one</code> as a JSON string */
+    static String one = '{"id":"one","value":"FIRST!","numValue":0,"sub":null}'
+
+    /** Document ID <code>two</code> as a JSON string */
+    static String two = '{"id":"two","value":"another","numValue":10,"sub":{"foo":"green","bar":"blue"}}'
+
+    /** Document ID <code>three</code> as a JSON string */
+    static String three = '{"id":"three","value":"","numValue":4,"sub":null}'
+
+    /** Document ID <code>four</code> as a JSON string */
+    static String four = '{"id":"four","value":"purple","numValue":17,"sub":{"foo":"green","bar":"red"}}'
+
+    /** Document ID <code>five</code> as a JSON string */
+    static String five = '{"id":"five","value":"purple","numValue":18,"sub":null}'
 }
diff --git a/src/groovy/src/test/groovy/solutions/bitbadger/documents/groovy/tests/integration/JsonFunctions.groovy b/src/groovy/src/test/groovy/solutions/bitbadger/documents/groovy/tests/integration/JsonFunctions.groovy
index f657d5e..992c403 100644
--- a/src/groovy/src/test/groovy/solutions/bitbadger/documents/groovy/tests/integration/JsonFunctions.groovy
+++ b/src/groovy/src/test/groovy/solutions/bitbadger/documents/groovy/tests/integration/JsonFunctions.groovy
@@ -3,6 +3,18 @@ package solutions.bitbadger.documents.groovy.tests.integration
 import solutions.bitbadger.documents.Configuration
 import solutions.bitbadger.documents.Dialect
 
+import static org.junit.jupiter.api.Assertions.*
+import static solutions.bitbadger.documents.groovy.tests.Types.TEST_TABLE
+
+/**
+ * Tests for the JSON-returning functions
+ *
+ * NOTE: PostgreSQL JSONB columns do not preserve the original JSON with which a document was stored. These tests are
+ * the most complex within the library, as they have split testing based on the backing data store. The PostgreSQL tests
+ * check IDs (and, in the case of ordered queries, which ones occur before which others) vs. the entire JSON string.
+ * Meanwhile, SQLite stores JSON as text, and will return exactly the JSON it was given when it was originally written.
+ * These tests can ensure the expected round-trip of the entire JSON string.
+ */
 final class JsonFunctions {
 
     /**
@@ -13,8 +25,372 @@ final class JsonFunctions {
      * @return The actual expected JSON based on the database being tested
      */
     static String maybeJsonB(String json) {
-        Configuration.dialect() == Dialect.SQLITE
-                ? json
-                : json.replace('":"', '": "').replace('","', '", "').replace('":[', '": [')
+        return switch (Configuration.dialect()) {
+            case Dialect.SQLITE -> json
+            case Dialect.POSTGRESQL -> json.replace ('":', '": ' ).replace (',"', ', "')
+        }
     }
+
+    /**
+     * Create a snippet of JSON to find a document ID
+     *
+     * @param id The ID of the document
+     * @return A connection-aware ID to check for presence and positioning
+     */
+    private static String docId(String id) {
+        return maybeJsonB("{\"id\":\"$id\"")
+    }
+
+    static void allDefault(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        def json = db.conn.jsonAll(TEST_TABLE)
+        assertTrue(json.startsWith("["), "JSON should start with '[' ($json)")
+        switch (Configuration.dialect()) {
+            case Dialect.SQLITE:
+                assertTrue(json.contains(JsonDocument.one), "Document 'one' not found in JSON ($json)")
+                assertTrue(json.contains(JsonDocument.two), "Document 'two' not found in JSON ($json)")
+                assertTrue(json.contains(JsonDocument.three), "Document 'three' not found in JSON ($json)")
+                assertTrue(json.contains(JsonDocument.four), "Document 'four' not found in JSON ($json)")
+                assertTrue(json.contains(JsonDocument.five), "Document 'five' not found in JSON ($json)")
+                break
+            case Dialect.POSTGRESQL:
+                assertTrue(json.contains(docId("one")), "Document 'one' not found in JSON ($json)")
+                assertTrue(json.contains(docId("two")), "Document 'two' not found in JSON ($json)")
+                assertTrue(json.contains(docId("three")), "Document 'three' not found in JSON ($json)")
+                assertTrue(json.contains(docId("four")), "Document 'four' not found in JSON ($json)")
+                assertTrue(json.contains(docId("five")), "Document 'five' not found in JSON ($json)")
+                break
+        }
+        assertTrue(json.endsWith("]"), "JSON should end with ']' ($json)")
+    }
+
+    static void allEmpty(ThrowawayDatabase db) =
+    assertEquals("[]", db.conn.jsonAll(TEST_TABLE), "There should have been no documents returned")
+
+    static void byIdString(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        val json = db.conn.jsonById(TEST_TABLE, "two")
+        when (Configuration.dialect()) {
+            Dialect.SQLITE -> assertEquals(JsonDocument.two, json, "An incorrect document was returned")
+            Dialect.POSTGRESQL -> assertTrue(json.contains(docId("two")), "An incorrect document was returned ($json)")
+        }
+    }
+
+    static void byIdNumber(ThrowawayDatabase db) {
+        Configuration.idField = "key"
+        try {
+            db.conn.insert(TEST_TABLE, NumIdDocument(18, "howdy"))
+            assertEquals(
+                    maybeJsonB("{\"key\":18,\"text\":\"howdy\"}"), db.conn.jsonById(TEST_TABLE, 18),
+                    "The document should have been found by numeric ID"
+            )
+        } finally {
+            Configuration.idField = "id"
+        }
+    }
+
+    static void byIdNotFound(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        assertEquals("{}", db.conn.jsonById(TEST_TABLE, "x"), "There should have been no document returned")
+    }
+
+    static void byFieldsMatch(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        val json = db.conn.jsonByFields(
+                TEST_TABLE, listOf(Field.any("value", listOf("blue", "purple")), Field.exists("sub")), FieldMatch.ALL
+        )
+        when (Configuration.dialect()) {
+            Dialect.SQLITE -> assertEquals("[${JsonDocument.four}]", json, "The incorrect document was returned")
+            Dialect.POSTGRESQL -> {
+                assertTrue(json.startsWith("["), "JSON should start with '[' ($json)")
+                assertTrue(json.contains(docId("four")),"The incorrect document was returned ($json)")
+                assertTrue(json.endsWith("]"), "JSON should end with ']' ($json)")
+            }
+        }
+    }
+
+    static void byFieldsMatchOrdered(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        val json = db.conn.jsonByFields(
+                TEST_TABLE, listOf(Field.equal("value", "purple")), orderBy = listOf(Field.named("id"))
+        )
+        when (Configuration.dialect()) {
+            Dialect.SQLITE -> assertEquals(
+                    "[${JsonDocument.five},${JsonDocument.four}]", json, "The documents were not ordered correctly"
+            )
+
+            Dialect.POSTGRESQL -> {
+                val fiveIdx = json.indexOf(docId("five"))
+                val fourIdx = json.indexOf(docId("four"))
+                assertTrue(json.startsWith("["), "JSON should start with '[' ($json)")
+                assertTrue(fiveIdx >= 0, "Document 'five' not found ($json)")
+                assertTrue(fourIdx >= 0, "Document 'four' not found ($json)")
+                assertTrue(fiveIdx < fourIdx, "Document 'five' should have been before 'four' ($json)")
+                assertTrue(json.endsWith("]"), "JSON should end with ']' ($json)")
+            }
+        }
+    }
+
+    static void byFieldsMatchNumIn(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        val json = db.conn.jsonByFields(TEST_TABLE, listOf(Field.any("numValue", listOf(2, 4, 6, 8))))
+        when (Configuration.dialect()) {
+            Dialect.SQLITE -> assertEquals("[${JsonDocument.three}]", json, "The incorrect document was returned")
+            Dialect.POSTGRESQL -> {
+                assertTrue(json.startsWith("["), "JSON should start with '[' ($json)")
+                assertTrue(json.contains(docId("three")), "The incorrect document was returned ($json)")
+                assertTrue(json.endsWith("]"), "JSON should end with ']' ($json)")
+            }
+        }
+    }
+
+    static void byFieldsNoMatch(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        assertEquals(
+                "[]", db.conn.jsonByFields(TEST_TABLE, listOf(Field.greater("numValue", 100))),
+                "There should have been no documents returned"
+        )
+    }
+
+    static void byFieldsMatchInArray(ThrowawayDatabase db) {
+        ArrayDocument.testDocuments.forEach { db.conn.insert(TEST_TABLE, it) }
+        val json = db.conn.jsonByFields(TEST_TABLE, listOf(Field.inArray("values", TEST_TABLE, listOf("c"))))
+        assertTrue(json.startsWith("["), "JSON should start with '[' ($json)")
+        assertTrue(json.contains(docId("first")), "The 'first' document was not found ($json)")
+        assertTrue(json.contains(docId("second")), "The 'second' document was not found ($json)")
+        assertTrue(json.endsWith("]"), "JSON should end with ']' ($json)")
+    }
+
+    static void byFieldsNoMatchInArray(ThrowawayDatabase db) {
+        ArrayDocument.testDocuments.forEach { db.conn.insert(TEST_TABLE, it) }
+        assertEquals(
+                "[]", db.conn.jsonByFields(
+                TEST_TABLE, listOf(Field.inArray("values", TEST_TABLE, listOf("j")))
+        ), "There should have been no documents returned"
+        )
+    }
+
+    static void byContainsMatch(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        val json = db.conn.jsonByContains(TEST_TABLE, mapOf("value" to "purple"))
+        assertTrue(json.startsWith("["), "JSON should start with '[' ($json)")
+        when (Configuration.dialect()) {
+            Dialect.SQLITE -> {
+                assertTrue(json.contains(JsonDocument.four), "Document 'four' not found ($json)")
+                assertTrue(json.contains(JsonDocument.five), "Document 'five' not found ($json)")
+            }
+            Dialect.POSTGRESQL -> {
+                assertTrue(json.contains(docId("four")), "Document 'four' not found ($json)")
+                assertTrue(json.contains(docId("five")), "Document 'five' not found ($json)")
+            }
+        }
+        assertTrue(json.endsWith("]"), "JSON should end with ']' ($json)")
+    }
+
+    static void byContainsMatchOrdered(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        val json = db.conn.jsonByContains(
+                TEST_TABLE, mapOf("sub" to mapOf("foo" to "green")), listOf(Field.named("value"))
+        )
+        when (Configuration.dialect()) {
+            Dialect.SQLITE -> assertEquals(
+                    "[${JsonDocument.two},${JsonDocument.four}]", json, "The documents were not ordered correctly"
+            )
+            Dialect.POSTGRESQL -> {
+                val twoIdx = json.indexOf(docId("two"))
+                val fourIdx = json.indexOf(docId("four"))
+                assertTrue(json.startsWith("["), "JSON should start with '[' ($json)")
+                assertTrue(twoIdx >= 0, "Document 'two' not found ($json)")
+                assertTrue(fourIdx >= 0, "Document 'four' not found ($json)")
+                assertTrue(twoIdx < fourIdx, "Document 'two' should have been before 'four' ($json)")
+                assertTrue(json.endsWith("]"), "JSON should end with ']' ($json)")
+            }
+        }
+    }
+
+    static void byContainsNoMatch(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        assertEquals(
+                "[]",
+                db.conn.jsonByContains(TEST_TABLE, mapOf("value" to "indigo")),
+                "There should have been no documents returned"
+        )
+    }
+
+    static void byJsonPathMatch(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        val json = db.conn.jsonByJsonPath(TEST_TABLE, "$.numValue ? (@ > 10)")
+        assertTrue(json.startsWith("["), "JSON should start with '[' ($json)")
+        when (Configuration.dialect()) {
+            Dialect.SQLITE -> {
+                assertTrue(json.contains(JsonDocument.four), "Document 'four' not found ($json)")
+                assertTrue(json.contains(JsonDocument.five), "Document 'five' not found ($json)")
+            }
+            Dialect.POSTGRESQL -> {
+                assertTrue(json.contains(docId("four")), "Document 'four' not found ($json)")
+                assertTrue(json.contains(docId("five")), "Document 'five' not found ($json)")
+            }
+        }
+        assertTrue(json.endsWith("]"), "JSON should end with ']' ($json)")
+    }
+
+    static void byJsonPathMatchOrdered(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        val json = db.conn.jsonByJsonPath(TEST_TABLE, "$.numValue ? (@ > 10)", listOf(Field.named("id")))
+        when (Configuration.dialect()) {
+            Dialect.SQLITE -> assertEquals(
+                    "[${JsonDocument.five},${JsonDocument.four}]", json, "The documents were not ordered correctly"
+            )
+
+            Dialect.POSTGRESQL -> {
+                val fiveIdx = json.indexOf(docId("five"))
+                val fourIdx = json.indexOf(docId("four"))
+                assertTrue(json.startsWith("["), "JSON should start with '[' ($json)")
+                assertTrue(fiveIdx >= 0, "Document 'five' not found ($json)")
+                assertTrue(fourIdx >= 0, "Document 'four' not found ($json)")
+                assertTrue(fiveIdx < fourIdx, "Document 'five' should have been before 'four' ($json)")
+                assertTrue(json.endsWith("]"), "JSON should end with ']' ($json)")
+            }
+        }
+    }
+
+    static void byJsonPathNoMatch(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        assertEquals(
+                "[]",
+                db.conn.jsonByJsonPath(TEST_TABLE, "$.numValue ? (@ > 100)"),
+                "There should have been no documents returned"
+        )
+    }
+
+    static void firstByFieldsMatchOne(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        val json = db.conn.jsonFirstByFields(TEST_TABLE, listOf(Field.equal("value", "another")))
+        when (Configuration.dialect()) {
+            Dialect.SQLITE -> assertEquals(JsonDocument.two, json, "The incorrect document was returned")
+            Dialect.POSTGRESQL -> assertTrue(json.contains(docId("two")), "The incorrect document was returned ($json)")
+        }
+    }
+
+    static void firstByFieldsMatchMany(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        val json = db.conn.jsonFirstByFields(TEST_TABLE, listOf(Field.equal("sub.foo", "green")))
+        when (Configuration.dialect()) {
+            Dialect.SQLITE -> assertTrue(
+                    json.contains(JsonDocument.two) || json.contains(JsonDocument.four),
+                    "Expected document 'two' or 'four' ($json)"
+            )
+            Dialect.POSTGRESQL -> assertTrue(
+                    json.contains(docId("two")) || json.contains(docId("four")),
+                    "Expected document 'two' or 'four' ($json)"
+            )
+        }
+    }
+
+    static void firstByFieldsMatchOrdered(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        val json = db.conn.jsonFirstByFields(
+                TEST_TABLE, listOf(Field.equal("sub.foo", "green")), orderBy = listOf(Field.named("n:numValue DESC"))
+        )
+        when (Configuration.dialect()) {
+            Dialect.SQLITE -> assertEquals(JsonDocument.four, json, "An incorrect document was returned")
+            Dialect.POSTGRESQL -> assertTrue(json.contains(docId("four")), "An incorrect document was returned ($json)")
+        }
+    }
+
+    static void firstByFieldsNoMatch(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        assertEquals(
+                "{}",
+                db.conn.jsonFirstByFields(TEST_TABLE, listOf(Field.equal("value", "absent"))),
+                "There should have been no document returned"
+        )
+    }
+
+    static void firstByContainsMatchOne(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        val json = db.conn.jsonFirstByContains(TEST_TABLE, mapOf("value" to "FIRST!"))
+        when (Configuration.dialect()) {
+            Dialect.SQLITE -> assertEquals(JsonDocument.one, json, "An incorrect document was returned")
+            Dialect.POSTGRESQL -> assertTrue(json.contains(docId("one")), "An incorrect document was returned ($json)")
+        }
+    }
+
+    static void firstByContainsMatchMany(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        val json = db.conn.jsonFirstByContains(TEST_TABLE, mapOf("value" to "purple"))
+        when (Configuration.dialect()) {
+            Dialect.SQLITE -> assertTrue(
+                    json.contains(JsonDocument.four) || json.contains(JsonDocument.five),
+                    "Expected document 'four' or 'five' ($json)"
+            )
+            Dialect.POSTGRESQL -> assertTrue(
+                    json.contains(docId("four")) || json.contains(docId("five")),
+                    "Expected document 'four' or 'five' ($json)"
+            )
+        }
+    }
+
+    static void firstByContainsMatchOrdered(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        val json = db.conn.jsonFirstByContains(
+                TEST_TABLE, mapOf("value" to "purple"), listOf(Field.named("sub.bar NULLS FIRST"))
+        )
+        when (Configuration.dialect()) {
+            Dialect.SQLITE -> assertEquals(JsonDocument.five, json, "An incorrect document was returned")
+            Dialect.POSTGRESQL -> assertTrue(json.contains(docId("five")), "An incorrect document was returned ($json)")
+        }
+    }
+
+    static void firstByContainsNoMatch(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        assertEquals(
+                "{}",
+                db.conn.jsonFirstByContains(TEST_TABLE, mapOf("value" to "indigo")),
+                "There should have been no document returned"
+        )
+    }
+
+    static void firstByJsonPathMatchOne(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        val json = db.conn.jsonFirstByJsonPath(TEST_TABLE, "$.numValue ? (@ == 10)")
+        when (Configuration.dialect()) {
+            Dialect.SQLITE -> assertEquals(JsonDocument.two, json, "An incorrect document was returned")
+            Dialect.POSTGRESQL -> assertTrue(json.contains(docId("two")), "An incorrect document was returned ($json)")
+        }
+    }
+
+    static void firstByJsonPathMatchMany(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        val json = db.conn.jsonFirstByJsonPath(TEST_TABLE, "$.numValue ? (@ > 10)")
+        when (Configuration.dialect()) {
+            Dialect.SQLITE -> assertTrue(
+                    json.contains(JsonDocument.four) || json.contains(JsonDocument.five),
+                    "Expected document 'four' or 'five' ($json)"
+            )
+            Dialect.POSTGRESQL -> assertTrue(
+                    json.contains(docId("four")) || json.contains(docId("five")),
+                    "Expected document 'four' or 'five' ($json)"
+            )
+        }
+    }
+
+    static void firstByJsonPathMatchOrdered(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        val json = db.conn.jsonFirstByJsonPath(TEST_TABLE, "$.numValue ? (@ > 10)", listOf(Field.named("id DESC")))
+        when (Configuration.dialect()) {
+            Dialect.SQLITE -> assertEquals(JsonDocument.four, json, "An incorrect document was returned")
+            Dialect.POSTGRESQL -> assertTrue(json.contains(docId("four")), "An incorrect document was returned ($json)")
+        }
+    }
+
+    static void firstByJsonPathNoMatch(ThrowawayDatabase db) {
+        JsonDocument.load(db)
+        assertEquals(
+                "{}",
+                db.conn.jsonFirstByJsonPath(TEST_TABLE, "$.numValue ? (@ > 100)"),
+                "There should have been no document returned"
+        )
+    }
+
 }