diff --git a/src/analyze-action-env.test.ts b/src/analyze-action-env.test.ts
index aecbae4b02..e1538bf4b4 100644
--- a/src/analyze-action-env.test.ts
+++ b/src/analyze-action-env.test.ts
@@ -28,9 +28,7 @@ test("analyze action with RAM & threads from environment variables", async (t) =
   // it a bit to 20s.
   t.timeout(1000 * 20);
   await util.withTmpDir(async (tmpDir) => {
-    process.env["GITHUB_SERVER_URL"] = util.GITHUB_DOTCOM_URL;
-    process.env["GITHUB_REPOSITORY"] = "github/codeql-action-fake-repository";
-    process.env["GITHUB_API_URL"] = "https://api.github.com";
+    setupActionsVars(tmpDir, tmpDir);
     sinon
       .stub(statusReport, "createStatusReportBase")
       .resolves({} as statusReport.StatusReportBase);
@@ -54,7 +52,6 @@ test("analyze action with RAM & threads from environment variables", async (t) =
     const optionalInputStub = sinon.stub(actionsUtil, "getOptionalInput");
     optionalInputStub.withArgs("expect-error").returns("false");
     sinon.stub(api, "getGitHubVersion").resolves(gitHubVersion);
-    setupActionsVars(tmpDir, tmpDir);
     mockFeatureFlagApiEndpoint(200, {});
 
     // When there are no action inputs for RAM and threads, the action uses
diff --git a/src/analyze-action-input.test.ts b/src/analyze-action-input.test.ts
index 74c03923da..b2c56e119e 100644
--- a/src/analyze-action-input.test.ts
+++ b/src/analyze-action-input.test.ts
@@ -26,9 +26,7 @@ setupTests(test);
 test("analyze action with RAM & threads from action inputs", async (t) => {
   t.timeout(1000 * 20);
   await util.withTmpDir(async (tmpDir) => {
-    process.env["GITHUB_SERVER_URL"] = util.GITHUB_DOTCOM_URL;
-    process.env["GITHUB_REPOSITORY"] = "github/codeql-action-fake-repository";
-    process.env["GITHUB_API_URL"] = "https://api.github.com";
+    setupActionsVars(tmpDir, tmpDir);
     sinon
       .stub(statusReport, "createStatusReportBase")
       .resolves({} as statusReport.StatusReportBase);
@@ -51,7 +49,6 @@ test("analyze action with RAM & threads from action inputs", async (t) => {
     optionalInputStub.withArgs("expect-error").returns("false");
     sinon.stub(api, "getGitHubVersion").resolves(gitHubVersion);
     sinon.stub(gitUtils, "isAnalyzingDefaultBranch").resolves(true);
-    setupActionsVars(tmpDir, tmpDir);
     mockFeatureFlagApiEndpoint(200, {});
 
     process.env["CODEQL_THREADS"] = "1";
diff --git a/src/init-action-post-helper.test.ts b/src/init-action-post-helper.test.ts
index 5bdb674a14..ee18c8fcc7 100644
--- a/src/init-action-post-helper.test.ts
+++ b/src/init-action-post-helper.test.ts
@@ -15,7 +15,9 @@ import { parseRepositoryNwo } from "./repository";
 import {
   createFeatures,
   createTestConfig,
+  DEFAULT_ACTIONS_VARS,
   makeVersionInfo,
+  setupActionsVars,
   setupTests,
 } from "./testing-utils";
 import * as uploadLib from "./upload-lib";
@@ -28,8 +30,7 @@ setupTests(test);
 
 test("init-post action with debug mode off", async (t) => {
   return await util.withTmpDir(async (tmpDir) => {
-    process.env["GITHUB_REPOSITORY"] = "github/codeql-action-fake-repository";
-    process.env["RUNNER_TEMP"] = tmpDir;
+    setupActionsVars(tmpDir, tmpDir);
 
     const gitHubVersion: util.GitHubVersion = {
       type: util.GitHubVariant.DOTCOM,
@@ -62,8 +63,7 @@ test("init-post action with debug mode off", async (t) => {
 
 test("init-post action with debug mode on", async (t) => {
   return await util.withTmpDir(async (tmpDir) => {
-    process.env["GITHUB_REPOSITORY"] = "github/codeql-action-fake-repository";
-    process.env["RUNNER_TEMP"] = tmpDir;
+    setupActionsVars(tmpDir, tmpDir);
 
     const uploadAllAvailableDebugArtifactsSpy = sinon.spy();
     const printDebugLogsSpy = sinon.spy();
@@ -315,11 +315,7 @@ test("not uploading failed SARIF when `code-scanning` is not an enabled analysis
 
 test("saves overlay status when overlay-base analysis did not complete successfully", async (t) => {
   return await util.withTmpDir(async (tmpDir) => {
-    process.env["GITHUB_REPOSITORY"] = "github/codeql-action-fake-repository";
-    process.env["GITHUB_RUN_ID"] = "12345";
-    process.env["GITHUB_RUN_ATTEMPT"] = "1";
-    process.env["GITHUB_JOB"] = "analyze";
-    process.env["RUNNER_TEMP"] = tmpDir;
+    setupActionsVars(tmpDir, tmpDir);
     // Ensure analyze did not complete successfully.
     delete process.env[EnvVar.ANALYZE_DID_COMPLETE_SUCCESSFULLY];
 
@@ -375,9 +371,9 @@ test("saves overlay status when overlay-base analysis did not complete successfu
         builtOverlayBaseDatabase: false,
         job: {
           checkRunId: undefined,
-          workflowRunId: 12345,
-          workflowRunAttempt: 1,
-          name: "analyze",
+          workflowRunId: Number(DEFAULT_ACTIONS_VARS.GITHUB_RUN_ID),
+          workflowRunAttempt: Number(DEFAULT_ACTIONS_VARS.GITHUB_RUN_ATTEMPT),
+          name: DEFAULT_ACTIONS_VARS.GITHUB_JOB,
         },
       },
       "fourth arg should be the overlay status recording an unsuccessful build attempt with job details",
@@ -387,8 +383,7 @@ test("saves overlay status when overlay-base analysis did not complete successfu
 
 test("does not save overlay status when OverlayAnalysisStatusSave feature flag is disabled", async (t) => {
   return await util.withTmpDir(async (tmpDir) => {
-    process.env["GITHUB_REPOSITORY"] = "github/codeql-action-fake-repository";
-    process.env["RUNNER_TEMP"] = tmpDir;
+    setupActionsVars(tmpDir, tmpDir);
     // Ensure analyze did not complete successfully.
     delete process.env[EnvVar.ANALYZE_DID_COMPLETE_SUCCESSFULLY];
 
@@ -424,8 +419,7 @@ test("does not save overlay status when OverlayAnalysisStatusSave feature flag i
 
 test("does not save overlay status when build successful", async (t) => {
   return await util.withTmpDir(async (tmpDir) => {
-    process.env["GITHUB_REPOSITORY"] = "github/codeql-action-fake-repository";
-    process.env["RUNNER_TEMP"] = tmpDir;
+    setupActionsVars(tmpDir, tmpDir);
     // Mark analyze as having completed successfully.
     process.env[EnvVar.ANALYZE_DID_COMPLETE_SUCCESSFULLY] = "true";
 
@@ -461,8 +455,7 @@ test("does not save overlay status when build successful", async (t) => {
 
 test("does not save overlay status when overlay not enabled", async (t) => {
   return await util.withTmpDir(async (tmpDir) => {
-    process.env["GITHUB_REPOSITORY"] = "github/codeql-action-fake-repository";
-    process.env["RUNNER_TEMP"] = tmpDir;
+    setupActionsVars(tmpDir, tmpDir);
     delete process.env[EnvVar.ANALYZE_DID_COMPLETE_SUCCESSFULLY];
 
     sinon.stub(util, "checkDiskUsage").resolves({
@@ -547,9 +540,8 @@ async function testFailedSarifUpload(
     config.dbLocation = "path/to/database";
   }
   process.env["GITHUB_JOB"] = "analyze";
-  process.env["GITHUB_REPOSITORY"] = "github/codeql-action-fake-repository";
-  process.env["GITHUB_WORKSPACE"] =
-    "/home/runner/work/codeql-action/codeql-action";
+  process.env["GITHUB_REPOSITORY"] = DEFAULT_ACTIONS_VARS.GITHUB_REPOSITORY;
+  process.env["GITHUB_WORKSPACE"] = "/tmp";
   sinon
     .stub(actionsUtil, "getRequiredInput")
     .withArgs("matrix")
diff --git a/src/setup-codeql.test.ts b/src/setup-codeql.test.ts
index 5b1587ab0a..91ace0196c 100644
--- a/src/setup-codeql.test.ts
+++ b/src/setup-codeql.test.ts
@@ -353,8 +353,7 @@ test("getCodeQLSource correctly returns nightly CLI version when forced by FF",
   sinon.stub(api, "getApiClient").value(() => client);
 
   await withTmpDir(async (tmpDir) => {
-    setupActionsVars(tmpDir, tmpDir);
-    process.env["GITHUB_EVENT_NAME"] = "dynamic";
+    setupActionsVars(tmpDir, tmpDir, { GITHUB_EVENT_NAME: "dynamic" });
 
     const source = await setupCodeql.getCodeQLSource(
       undefined,
@@ -405,8 +404,7 @@ test("getCodeQLSource correctly returns latest version from toolcache when tools
     .returns(latestVersionPath);
 
   await withTmpDir(async (tmpDir) => {
-    setupActionsVars(tmpDir, tmpDir);
-    process.env["GITHUB_EVENT_NAME"] = "dynamic";
+    setupActionsVars(tmpDir, tmpDir, { GITHUB_EVENT_NAME: "dynamic" });
 
     const source = await setupCodeql.getCodeQLSource(
       "toolcache",
diff --git a/src/status-report.test.ts b/src/status-report.test.ts
index e051c54a27..6f4bb11f89 100644
--- a/src/status-report.test.ts
+++ b/src/status-report.test.ts
@@ -25,18 +25,14 @@ import { BuildMode, ConfigurationError, withTmpDir, wrapError } from "./util";
 setupTests(test);
 
 function setupEnvironmentAndStub(tmpDir: string) {
-  setupActionsVars(tmpDir, tmpDir);
+  setupActionsVars(tmpDir, tmpDir, {
+    GITHUB_EVENT_NAME: "dynamic",
+    GITHUB_RUN_ATTEMPT: "2",
+    GITHUB_RUN_ID: "100",
+  });
 
   process.env[EnvVar.ANALYSIS_KEY] = "analysis-key";
-  process.env["GITHUB_EVENT_NAME"] = "dynamic";
-  process.env["GITHUB_REF"] = "refs/heads/main";
-  process.env["GITHUB_REPOSITORY"] = "octocat/HelloWorld";
-  process.env["GITHUB_RUN_ATTEMPT"] = "2";
-  process.env["GITHUB_RUN_ID"] = "100";
-  process.env["GITHUB_SHA"] = "a".repeat(40);
   process.env["ImageVersion"] = "2023.05.19.1";
-  process.env["RUNNER_OS"] = "macOS";
-  process.env["RUNNER_TEMP"] = tmpDir;
 
   const getRequiredInput = sinon.stub(actionsUtil, "getRequiredInput");
   getRequiredInput.withArgs("matrix").resolves("input/matrix");
diff --git a/src/testing-utils.ts b/src/testing-utils.ts
index 3abc1f4f4c..8a7cf8e2d9 100644
--- a/src/testing-utils.ts
+++ b/src/testing-utils.ts
@@ -139,13 +139,40 @@ export function setupTests(test: TestFn<any>) {
   });
 }
 
+/**
+ * Default values for environment variables typically set in an Actions
+ * environment. Tests can override individual variables by passing them in the
+ * `overrides` parameter.
+ */
+export const DEFAULT_ACTIONS_VARS = {
+  GITHUB_ACTION_REPOSITORY: "github/codeql-action",
+  GITHUB_API_URL: "https://api.github.com",
+  GITHUB_EVENT_NAME: "push",
+  GITHUB_JOB: "test-job",
+  GITHUB_REF: "refs/heads/main",
+  GITHUB_REPOSITORY: "github/codeql-action-testing",
+  GITHUB_RUN_ATTEMPT: "1",
+  GITHUB_RUN_ID: "1",
+  GITHUB_SERVER_URL: "https://github.com",
+  GITHUB_SHA: "0".repeat(40),
+  GITHUB_WORKFLOW: "test-workflow",
+  RUNNER_OS: "Linux",
+} as const satisfies Record<string, string>;
+
 // Sets environment variables that make using some libraries designed for
 // use only on actions safe to use outside of actions.
-export function setupActionsVars(tempDir: string, toolsDir: string) {
+export function setupActionsVars(
+  tempDir: string,
+  toolsDir: string,
+  overrides?: Partial<Record<keyof typeof DEFAULT_ACTIONS_VARS, string>>,
+) {
+  const vars = { ...DEFAULT_ACTIONS_VARS, ...overrides };
+  for (const [key, value] of Object.entries(vars)) {
+    process.env[key] = value;
+  }
   process.env["RUNNER_TEMP"] = tempDir;
   process.env["RUNNER_TOOL_CACHE"] = toolsDir;
   process.env["GITHUB_WORKSPACE"] = tempDir;
-  process.env["GITHUB_EVENT_NAME"] = "push";
 }
 
 type LogLevel = "debug" | "info" | "warning" | "error";