Create basic parsing of CSV test data.

hack/test-flake-chart/flake_chart.js

@@ -1,18 +1,80 @@
 
+// Displays an error message to the UI. Any previous message will be erased.
 function displayError(message) {
   console.error(message);
 }
 
+// Creates a generator that reads the response body one line at a time.
+async function* bodyByLinesIterator(response) {
+  // TODO: Replace this with something that actually reads the body line by line
+  // (since the file can be big).
+  const lines = (await response.text()).split("\n");
+  for (let line of lines) {
+    // Skip any empty lines (most likely at the end).
+    if (line !== "") {
+      yield line;
+    }
+  }
+}
+
+// Determines whether `str` matches at least one value in `enumObject`.
+function isValidEnumValue(enumObject, str) {
+  for (const enumKey in enumObject) {
+    if (enumObject[enumKey] === str) {
+      return true;
+    }
+  }
+  return false;
+}
+
+// Enum for test status.
+const testStatus = {
+  PASSED: "Passed",
+  FAILED: "Failed",
+  SKIPPED: "Skipped"
+}
+
 async function init() {
-  const response = await fetch("content.txt");
+  const response = await fetch("data.csv");
   if (!response.ok) {
     const responseText = await response.text();
     displayError(`Failed to fetch data from GCS bucket. Error: ${responseText}`);
     return;
   }
 
-  const responseText = await response.text();
-  console.log(responseText);
+  const lines = bodyByLinesIterator(response);
+  // Consume the header to ensure the data has the right number of fields.
+  const header = (await lines.next()).value;
+  if (header.split(",").length != 5) {
+    displayError(`Fetched CSV data contains wrong number of fields. Expected: 5. Actual Header: "${header}"`);
+    return;
+  }
+
+  const testData = [];
+  for await (const line of lines) {
+    const splitLine = line.split(",");
+    if (splitLine.length != 5) {
+      console.warn(`Found line with wrong number of fields. Actual: ${splitLine.length} Expected: 5. Line: "${line}"`);
+      continue;
+    }
+    if (!isValidEnumValue(testStatus, splitLine[4])) {
+      console.warn(`Invalid test status provided. Actual: ${splitLine[4]} Expected: One of ${Object.values(testStatus).join(", ")}`);
+      continue;
+    }
+    testData.push({
+      commit: splitLine[0],
+      date: new Date(splitLine[1]),
+      environment: splitLine[2],
+      name: splitLine[3],
+      status: splitLine[4]
+    });
+  }
+  if (testData.length == 0) {
+    displayError("Fetched CSV data is empty or poorly formatted.");
+    return;
+  }
+
+  console.log(testData);
 }
 
 init();