Enable session affinity for canaries (#7371)

rootfs/etc/nginx/lua/test/util/split_test.lua

@@ -0,0 +1,57 @@
+local split = require("util.split")
+
+describe("split", function()
+
+  describe("get_last_value", function()
+    it("splits value of an upstream variable and returns last value", function()
+      for _, case in ipairs({{"127.0.0.1:26157 : 127.0.0.1:26158", "127.0.0.1:26158"},
+                             {"127.0.0.1:26157, 127.0.0.1:26158", "127.0.0.1:26158"},
+                             {"127.0.0.1:26158", "127.0.0.1:26158"}}) do
+        local last = split.get_last_value(case[1])
+        assert.equal(case[2], last)
+      end
+    end)
+  end)
+
+  describe("split_string", function()
+
+    it("returns empty array if input string is empty", function()
+      local splits, len = split.split_string("", ",")
+      assert.equal(0, len)
+      assert.is.truthy(splits)
+    end)
+
+    it("returns empty array if input string is nil", function()
+      local splits, len = split.split_string(nil, ",")
+      assert.equal(0, len)
+      assert.is.truthy(splits)
+    end)
+
+    it("returns empty array if delimiter is empty", function()
+      local splits, len = split.split_string("1,2", "")
+      assert.equal(0, len)
+      assert.is.truthy(splits)
+    end)
+
+    it("returns empty array delimiter is nil", function()
+      local splits, len = split.split_string("1,2", nil)
+      assert.equal(0, len)
+      assert.is.truthy(splits)
+    end)
+
+    it("returns array of 1 value if input string is not a list", function()
+      local splits, len = split.split_string("123", ",")
+      assert.equal(1, len)
+      assert.equal("123", splits[1])
+    end)
+
+    it("returns array of values extracted from the input string", function()
+      local splits, len = split.split_string("1,2,3", ",")
+      assert.equal(3, len)
+      assert.equal("1", splits[1])
+      assert.equal("2", splits[2])
+      assert.equal("3", splits[3])
+    end)
+
+  end)
+end)