1 files changed, 96 insertions, 0 deletions
diff --git a/std/log/handlers_test.ts b/std/log/handlers_test.ts
new file mode 100644
index 000000000..329541fa1
--- /dev/null
+++ b/std/log/handlers_test.ts
@@ -0,0 +1,96 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+import { test } from "../testing/mod.ts";
+import { assertEquals } from "../testing/asserts.ts";
+import { LogLevel, getLevelName, getLevelByName } from "./levels.ts";
+import { BaseHandler } from "./handlers.ts";
+
+class TestHandler extends BaseHandler {
+  public messages: string[] = [];
+
+  public log(str: string): void {
+    this.messages.push(str);
+  }
+}
+
+test(function simpleHandler(): void {
+  const cases = new Map<number, string[]>([
+    [
+      LogLevel.DEBUG,
+      [
+        "DEBUG debug-test",
+        "INFO info-test",
+        "WARNING warning-test",
+        "ERROR error-test",
+        "CRITICAL critical-test"
+      ]
+    ],
+    [
+      LogLevel.INFO,
+      [
+        "INFO info-test",
+        "WARNING warning-test",
+        "ERROR error-test",
+        "CRITICAL critical-test"
+      ]
+    ],
+    [
+      LogLevel.WARNING,
+      ["WARNING warning-test", "ERROR error-test", "CRITICAL critical-test"]
+    ],
+    [LogLevel.ERROR, ["ERROR error-test", "CRITICAL critical-test"]],
+    [LogLevel.CRITICAL, ["CRITICAL critical-test"]]
+  ]);
+
+  for (const [testCase, messages] of cases.entries()) {
+    const testLevel = getLevelName(testCase);
+    const handler = new TestHandler(testLevel);
+
+    for (const levelName in LogLevel) {
+      const level = getLevelByName(levelName);
+      handler.handle({
+        msg: `${levelName.toLowerCase()}-test`,
+        args: [],
+        datetime: new Date(),
+        level: level,
+        levelName: levelName
+      });
+    }
+
+    assertEquals(handler.level, testCase);
+    assertEquals(handler.levelName, testLevel);
+    assertEquals(handler.messages, messages);
+  }
+});
+
+test(function testFormatterAsString(): void {
+  const handler = new TestHandler("DEBUG", {
+    formatter: "test {levelName} {msg}"
+  });
+
+  handler.handle({
+    msg: "Hello, world!",
+    args: [],
+    datetime: new Date(),
+    level: LogLevel.DEBUG,
+    levelName: "DEBUG"
+  });
+
+  assertEquals(handler.messages, ["test DEBUG Hello, world!"]);
+});
+
+test(function testFormatterAsFunction(): void {
+  const handler = new TestHandler("DEBUG", {
+    formatter: (logRecord): string =>
+      `fn formmatter ${logRecord.levelName} ${logRecord.msg}`
+  });
+
+  handler.handle({
+    msg: "Hello, world!",
+    args: [],
+    datetime: new Date(),
+    level: LogLevel.ERROR,
+    levelName: "ERROR"
+  });
+
+  assertEquals(handler.messages, ["fn formmatter ERROR Hello, world!"]);
+});