From fd7f08e73ee87cf9e1a3d6acab93b11079522302 Mon Sep 17 00:00:00 2001
From: Anton Keks <anton@azib.net>
Date: Sun, 16 Feb 2025 21:46:19 +0200
Subject: [PATCH] core: TSID.deterministic introduced for using in test data
 generation

---
 CHANGELOG.md          |  2 +-
 core/src/TSID.kt      |  9 ++++++---
 core/test/TSIDTest.kt | 12 ++++++++++++
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9cd09c94..fe75e380 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Unreleased
 * jdbc: add helpful details to Postgres exception "no hstore extension installed"
-* core: TSID now can use a preconfigured random seed using TSID_SEED, good for test data
+* core: TSID.deterministic introduced for using in test data generation
 * json: TSGenerator updates
   * wraps records with enum keys into Partial<T> to avoid TS wanting all the keys to be present
   * outputs provided custom types as separate types and references them
diff --git a/core/src/TSID.kt b/core/src/TSID.kt
index dd1c65c9..e8716b24 100644
--- a/core/src/TSID.kt
+++ b/core/src/TSID.kt
@@ -4,6 +4,7 @@ import java.lang.System.currentTimeMillis
 import java.security.SecureRandom
 import java.time.Instant
 import java.util.concurrent.atomic.AtomicInteger
+import java.util.concurrent.atomic.AtomicLong
 
 /**
  * Time-Sorted unique ID, a more compact and DB index-friendly alternative to UUID.
@@ -14,11 +15,13 @@ import java.util.concurrent.atomic.AtomicInteger
     const val RANDOM_BITS = 22
     const val RANDOM_MASK = 0x003fffff
     val EPOCH = Instant.parse(Config.optional("TSID_EPOCH", "2022-10-21T03:45:00.000Z")).toEpochMilli()
-    val random = Config.optional("TSID_SEED")?.toByteArray()?.let { SecureRandom(it) } ?: SecureRandom()
-    val counter = AtomicInteger()
-    @Volatile var lastTime = 0L
+    private var random = SecureRandom()
+    private val counter = AtomicInteger()
+    @Volatile private var lastTime = 0L
+    var deterministic: AtomicLong? = null
 
     fun generateValue(): Long {
+      deterministic?.let { return it.incrementAndGet() }
       val time = (currentTimeMillis() - EPOCH) shl RANDOM_BITS
       if (time != lastTime) {
         counter.set(random.nextInt())
diff --git a/core/test/TSIDTest.kt b/core/test/TSIDTest.kt
index a7e66379..504876bb 100644
--- a/core/test/TSIDTest.kt
+++ b/core/test/TSIDTest.kt
@@ -1,10 +1,12 @@
 package klite
 
+import ch.tutteli.atrium.api.fluent.en_GB.toBeGreaterThan
 import ch.tutteli.atrium.api.fluent.en_GB.toBeLessThanOrEqualTo
 import ch.tutteli.atrium.api.fluent.en_GB.toEqual
 import ch.tutteli.atrium.api.verbs.expect
 import org.junit.jupiter.api.Test
 import java.lang.System.currentTimeMillis
+import java.util.concurrent.atomic.AtomicLong
 
 typealias Id = TSID<Any>
 
@@ -30,4 +32,14 @@ class TSIDTest {
     for (i in 1..1000000) ids.add(Id())
     expect(ids.size).toEqual(1000000)
   }
+
+  @Test
+  fun deterministic() {
+    TSID.deterministic = AtomicLong(123123123)
+    expect(TSID<Any>().toString()).toEqual("21ayes")
+    expect(TSID<Any>().toString()).toEqual("21ayet")
+    expect(TSID<Any>().toString()).toEqual("21ayeu")
+    TSID.deterministic = null
+    expect(TSID<Any>().toString().length).toBeGreaterThan(8)
+  }
 }