diff --git a/.github/workflows/rubyci-alerts.yml b/.github/workflows/rubyci-alerts.yml
index 1bcf2c319..b4f03ee7e 100644
--- a/.github/workflows/rubyci-alerts.yml
+++ b/.github/workflows/rubyci-alerts.yml
@@ -12,7 +12,7 @@ jobs:
 
       - uses: ruby/setup-ruby@e81a8fa391b11a595c1b7ed84177cc0fe02faf83 # v1.328.0
         with:
-          ruby-version: 2.7
+          ruby-version: "4.0"
 
       - name: Use master branch
         run: git checkout master
diff --git a/.github/workflows/rubyci-screenshot.yml b/.github/workflows/rubyci-screenshot.yml
deleted file mode 100644
index 3c59b0482..000000000
--- a/.github/workflows/rubyci-screenshot.yml
+++ /dev/null
@@ -1,35 +0,0 @@
-name: rubyci-screenshot
-
-on:
-  push:
-    branches:
-      - master
-  schedule:
-    - cron: '30 14 * * *' # Daily at 14:30 UTC
-
-
-jobs:
-  latest:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
-
-      - uses: ruby/setup-ruby@e81a8fa391b11a595c1b7ed84177cc0fe02faf83 # v1.328.0
-        with:
-          ruby-version: 2.7
-
-      - name: Setup the environment
-        run: |
-          sudo snap install chromium
-          bundle install
-
-      - name: Run the script
-        run: bundle exec ruby rubyci-screenshot.rb
-        env:
-          RUBYCI_SCREENSHOT_SLACK_API_TOKEN: ${{ secrets.RUBYCI_SCREENSHOT_SLACK_API_TOKEN }}
-          RUBYCI_SCREENSHOT_SLACK_CHANNEL_ID: ${{ secrets.RUBYCI_SCREENSHOT_SLACK_CHANNEL_ID }}
-
-#      - uses: actions/upload-artifact@master
-#        with:
-#          name: rubyci-screenshot
-#          path: rubyci.png
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
new file mode 100644
index 000000000..0185add6f
--- /dev/null
+++ b/.github/workflows/test.yml
@@ -0,0 +1,26 @@
+name: test
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+
+      - uses: ruby/setup-ruby@e81a8fa391b11a595c1b7ed84177cc0fe02faf83 # v1.328.0
+        with:
+          ruby-version: "4.0"
+          bundler-cache: true
+
+      - name: Run the tests
+        run: bundle exec rake test
diff --git a/.gitignore b/.gitignore
deleted file mode 100644
index 77497590c..000000000
--- a/.gitignore
+++ /dev/null
@@ -1,2 +0,0 @@
-rubyci.orig.png
-rubyci.png
diff --git a/Gemfile b/Gemfile
index dfba848bc..eb8619204 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,3 +1,4 @@
 source "https://rubygems.org"
 
-gem "selenium-webdriver"
+gem "rake"
+gem "test-unit"
diff --git a/Gemfile.lock b/Gemfile.lock
index b176b7cfe..4c27565fe 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,17 +1,17 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    childprocess (3.0.0)
-    rubyzip (3.4.0)
-    selenium-webdriver (3.142.6)
-      childprocess (>= 0.5, < 4.0)
-      rubyzip (>= 1.2.2)
+    power_assert (3.1.0)
+    rake (13.4.2)
+    test-unit (3.7.8)
+      power_assert
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
-  selenium-webdriver
+  rake
+  test-unit
 
 BUNDLED WITH
-   2.1.2
+  4.0.20
diff --git a/Rakefile b/Rakefile
new file mode 100644
index 000000000..5d28d9f1b
--- /dev/null
+++ b/Rakefile
@@ -0,0 +1,5 @@
+require "rake/testtask"
+
+Rake::TestTask.new
+
+task default: :test
diff --git a/rubyci-alerts.rb b/rubyci-alerts.rb
index fccc7ae59..3e4ad773d 100644
--- a/rubyci-alerts.rb
+++ b/rubyci-alerts.rb
@@ -136,21 +136,23 @@ def filter_failure_reports(failure_reports, timestamps)
   end
 end
 
-begin
-  timestamps = {}
-  timestamps = JSON.parse(File.read(TIMESTAMPS_JSON))
-
-  servers = get_servers
-  failure_reports = get_failure_reports(servers)
-  filter_failure_reports(failure_reports, timestamps)
-  failure_reports.each do |_key, report|
-    notify_simpler_alerts(report)
-  end
+if __FILE__ == $0
+  begin
+    timestamps = {}
+    timestamps = JSON.parse(File.read(TIMESTAMPS_JSON))
+
+    servers = get_servers
+    failure_reports = get_failure_reports(servers)
+    filter_failure_reports(failure_reports, timestamps)
+    failure_reports.each do |_key, report|
+      notify_simpler_alerts(report)
+    end
 
-  File.write(TIMESTAMPS_JSON, JSON.pretty_generate(timestamps))
-rescue => e
-  NOTIFY_CHANNELS.each do |channel|
-    notify_slack("ruby/rubyci-alerts failed: #{e.class}: #{ escape(e.message) }", channel: channel)
+    File.write(TIMESTAMPS_JSON, JSON.pretty_generate(timestamps))
+  rescue => e
+    NOTIFY_CHANNELS.each do |channel|
+      notify_slack("ruby/rubyci-alerts failed: #{e.class}: #{ escape(e.message) }", channel: channel)
+    end
+    puts e.backtrace
   end
-  puts e.backtrace
 end
diff --git a/rubyci-screenshot.rb b/rubyci-screenshot.rb
deleted file mode 100644
index 77ac16f13..000000000
--- a/rubyci-screenshot.rb
+++ /dev/null
@@ -1,79 +0,0 @@
-#!/usr/bin/env ruby
-
-require "selenium-webdriver"
-require "net/http"
-require "openssl"
-
-SLACK_API_TOKEN = ENV["RUBYCI_SCREENSHOT_SLACK_API_TOKEN"]
-CHANNEL_ID = ENV["RUBYCI_SCREENSHOT_SLACK_CHANNEL_ID"]
-FILES_UPLOAD_URI = "https://slack.com/api/files.upload"
-
-Dir.chdir(__dir__)
-
-system("/snap/bin/chromium.chromedriver", "-v")
-Selenium::WebDriver::Chrome::Service.driver_path = "/snap/bin/chromium.chromedriver"
-
-options = Selenium::WebDriver::Chrome::Options.new
-options.add_argument("--headless")
-options.add_argument("--disable-gpu")
-options.add_argument("--disable-dev-shm-usage")
-options.add_argument("--no-sandbox")
-options.add_argument("--window-size=1280,3000")
-driver = Selenium::WebDriver.for(:chrome, options: options)
-
-driver.navigate.to("https://rubyci.org")
-driver.execute_script(<<END)
-let IGNORED_SERVERS = [
-// "Debian 10.0(testing) x86_64",
-];
-let trs = document.getElementsByTagName("tr");
-let removed_entries = [];
-for (let i = 0; i < trs.length; i++) {
-  let tr = trs[i];
-  let tds = tr.children;
-  for(let j = 0; j < tds.length; j++) {
-    let td = tds[j];
-    if (td.className == "branch" && td.textContent != "master") {
-      removed_entries.push(tr);
-    }
-    if (td.className == "server" && IGNORED_SERVERS.includes(td.textContent)) {
-      removed_entries.push(tr);
-    }
-  }
-}
-for (let i = 0; i < removed_entries.length; i++) {
-  removed_entries[i].remove();
-}
-END
-elem = driver.find_elements(:tag_name, "table")[0]
-loc = elem.location
-width  = elem.css_value("width").to_i
-height = elem.css_value("height").to_i
-
-driver.save_screenshot("rubyci.orig.png")
-crop = "#{ width }x#{ height }+#{ loc.x }+#{ loc.y }"
-system("convert", "rubyci.orig.png", "-crop", crop, "rubyci.png")
-
-unless SLACK_API_TOKEN
-  puts "SLACK_API_TOKEN is not specified"
-  exit
-end
-
-filename = Time.now.strftime("rubyci-%Y%m%d.png")
-open("rubyci.png", "rb") do |f|
-  data = [
-    ["token", SLACK_API_TOKEN],
-    ["channels", CHANNEL_ID],
-    ["filename", filename],
-    ["filetype", "png"],
-    ["title", filename],
-    ["file", f, { filename: filename, content_type: "image/png" } ],
-  ]
-  uri = URI.parse(FILES_UPLOAD_URI)
-  req = Net::HTTP::Post.new(uri.path)
-  req.set_form(data, "multipart/form-data")
-  http = Net::HTTP.new(uri.host, uri.port)
-  http.use_ssl = true
-  http.verify_mode = OpenSSL::SSL::VERIFY_NONE
-  http.request(req)
-end
diff --git a/test/fixtures/reports.json b/test/fixtures/reports.json
new file mode 100644
index 000000000..22170a289
--- /dev/null
+++ b/test/fixtures/reports.json
@@ -0,0 +1,50 @@
+[
+  {
+    "id": 4448056,
+    "server_id": 122,
+    "datetime": "2026-10-13T20:29:06.000Z",
+    "branch": "master",
+    "revision": "7ad8db2311523bc1af6a97154a65bb56758d8f7a",
+    "summary": "7ad8db23115 ruby (osx1400arm) 67W failed(dist) (diff:test-all,dist,success)",
+    "created_at": "2026-10-13T21:21:40.268Z",
+    "updated_at": "2026-10-13T21:21:40.268Z",
+    "option": null,
+    "ltsv": "host:osx1400arm\tdepsuffixed_name:ruby-master\tstart_time:20261013T202906Z\tresult:failure\ttitle:7ad8db23115 ruby (osx1400arm) 67W failed(dist)\tcompressed_loghtml_relpath:log/20261013T202906Z.log.html.gz\tcompressed_failhtml_relpath:log/20261013T202906Z.fail.html.gz\tcompressed_diffhtml_relpath:log/20261013T202906Z.diff.html.gz\tdifferent_sections:test-all,dist,success\tversion:7ad8db23115 ruby\tdep_versions:[]\thostname:(osx1400arm)\twarn:67W\tmark:\tstatus:\tfailure_dist:failed(dist)\thttps://github.com/ruby/ruby:7ad8db2311523bc1af6a97154a65bb56758d8f7a\truby_rev:7ad8db23115"
+  },
+  {
+    "id": 4448111,
+    "server_id": 122,
+    "datetime": "2026-10-13T21:45:04.000Z",
+    "branch": "master",
+    "revision": "67abedae69744b89fb477f96568a9363addfb469",
+    "summary": "67abedae697 ruby (osx1400arm) 3W success (diff:src,miniversion,version,test-all,rubyspec,dist)",
+    "created_at": "2026-10-13T22:51:22.807Z",
+    "updated_at": "2026-10-13T22:51:22.807Z",
+    "option": null,
+    "ltsv": "host:osx1400arm\tdepsuffixed_name:ruby-master\tstart_time:20261013T214504Z\tresult:success\ttitle:67abedae697 ruby (osx1400arm) 3W\tcompressed_loghtml_relpath:log/20261013T214504Z.log.html.gz\tcompressed_failhtml_relpath:log/20261013T214504Z.fail.html.gz\tcompressed_diffhtml_relpath:log/20261013T214504Z.diff.html.gz\tdifferent_sections:src,miniversion,version,test-all,rubyspec,dist\tversion:67abedae697 ruby\tdep_versions:[]\thostname:(osx1400arm)\twarn:3W\tmark:\tstatus:\thttps://github.com/ruby/ruby:67abedae69744b89fb477f96568a9363addfb469\truby_rev:67abedae697"
+  },
+  {
+    "id": 4448055,
+    "server_id": 122,
+    "datetime": "2026-10-13T20:29:06.000Z",
+    "branch": "3.3",
+    "revision": "7ad8db2311523bc1af6a97154a65bb56758d8f7a",
+    "summary": "7ad8db23115 ruby (osx1400arm) 67W failed(dist) (diff:test-all,dist,success)",
+    "created_at": "2026-10-13T21:21:40.268Z",
+    "updated_at": "2026-10-13T21:21:40.268Z",
+    "option": null,
+    "ltsv": "host:osx1400arm\tdepsuffixed_name:ruby-3.3\tstart_time:20261013T202906Z\tresult:failure\ttitle:7ad8db23115 ruby (osx1400arm) 67W failed(dist)\tcompressed_loghtml_relpath:log/20261013T202906Z.log.html.gz\tcompressed_failhtml_relpath:log/20261013T202906Z.fail.html.gz\tcompressed_diffhtml_relpath:log/20261013T202906Z.diff.html.gz\tdifferent_sections:test-all,dist,success\tversion:7ad8db23115 ruby\tdep_versions:[]\thostname:(osx1400arm)\twarn:67W\tmark:\tstatus:\tfailure_dist:failed(dist)\thttps://github.com/ruby/ruby:7ad8db2311523bc1af6a97154a65bb56758d8f7a\truby_rev:7ad8db23115"
+  },
+  {
+    "id": 4447990,
+    "server_id": 40,
+    "datetime": "2026-10-13T18:30:12.000Z",
+    "branch": "master",
+    "revision": "15212f6c1cf04e18c43ca44601f525a3bbf32b62",
+    "summary": "15212f6c1cf ruby (icc-x64) 12W failed(test-all) (diff:test-all)",
+    "created_at": "2026-10-13T19:20:41.000Z",
+    "updated_at": "2026-10-13T19:20:41.000Z",
+    "option": null,
+    "ltsv": "host:icc-x64\tdepsuffixed_name:ruby-master\tstart_time:20261013T183012Z\tresult:failure\ttitle:15212f6c1cf ruby (icc-x64) 12W failed(test-all)\tcompressed_loghtml_relpath:log/20261013T183012Z.log.html.gz\tcompressed_failhtml_relpath:log/20261013T183012Z.fail.html.gz\tcompressed_diffhtml_relpath:log/20261013T183012Z.diff.html.gz\tdifferent_sections:test-all\tversion:15212f6c1cf ruby\tdep_versions:[]\thostname:(icc-x64)\twarn:12W\tmark:\tstatus:\tfailure_test-all:failed(test-all)\thttps://github.com/ruby/ruby:15212f6c1cf04e18c43ca44601f525a3bbf32b62\truby_rev:15212f6c1cf"
+  }
+]
diff --git a/test/fixtures/servers.json b/test/fixtures/servers.json
new file mode 100644
index 000000000..25c4dbc5c
--- /dev/null
+++ b/test/fixtures/servers.json
@@ -0,0 +1,20 @@
+[
+  {
+    "id": 40,
+    "name": "icc 2025.3 x64 (Ubuntu)",
+    "uri": "http://rubyci.s3.amazonaws.com/icc-x64/",
+    "created_at": "2015-03-26T04:15:50.556Z",
+    "updated_at": "2026-09-10T06:53:58.177Z",
+    "ordinal": 17.0,
+    "eol_date": "2029-04-30"
+  },
+  {
+    "id": 122,
+    "name": "macOS 14.8 Sonoma",
+    "uri": "http://rubyci.s3.amazonaws.com/osx1400arm/",
+    "created_at": "2024-10-30T03:19:22.970Z",
+    "updated_at": "2026-02-13T08:22:13.596Z",
+    "ordinal": 14.68,
+    "eol_date": null
+  }
+]
diff --git a/test/test_rubyci_alerts.rb b/test/test_rubyci_alerts.rb
new file mode 100644
index 000000000..ff8e5212b
--- /dev/null
+++ b/test/test_rubyci_alerts.rb
@@ -0,0 +1,41 @@
+require "test/unit"
+require_relative "../rubyci-alerts"
+
+class TestRubyCIAlerts < Test::Unit::TestCase
+  FIXTURES = File.join(__dir__, "fixtures")
+
+  # URI.open falls back to Kernel#open for a local path, so the fixtures go
+  # through the real fetch_json.
+  def fetch_json(url)
+    super(File.join(FIXTURES, File.basename(url)))
+  end
+
+  def test_get_failure_reports
+    reports = get_failure_reports(get_servers).map {|_key, report| report.to_h }
+    assert_equal [
+      {
+        name: "macOS 14.8 Sonoma",
+        commit: "7ad8db23115",
+        fail_uri: "http://rubyci.s3.amazonaws.com/osx1400arm/ruby-master/log/20261013T202906Z.fail.html.gz",
+        shortsummary: "67W failed(dist)",
+      },
+      {
+        name: "icc 2025.3 x64 (Ubuntu)",
+        commit: "15212f6c1cf",
+        fail_uri: "http://rubyci.s3.amazonaws.com/icc-x64/ruby-master/log/20261013T183012Z.fail.html.gz",
+        shortsummary: "12W failed(test-all)",
+      },
+    ], reports
+  end
+
+  def test_filter_failure_reports
+    reports = get_failure_reports(get_servers)
+    notified = Time.iso8601("2026-10-13T20:29:06Z").to_i
+    timestamps = { "122" => notified }
+
+    filter_failure_reports(reports, timestamps)
+
+    assert_equal ["icc 2025.3 x64 (Ubuntu)"], reports.map {|_key, report| report.name }
+    assert_equal({ "122" => notified, "40" => Time.iso8601("2026-10-13T18:30:12Z").to_i }, timestamps)
+  end
+end