Read [data-turbo-action] during Form Submissions

Closes hotwired/turbo-ios#44
Follow-up to #231

---

This commit follows-up [#231][], which added `[data-turbo-action]`
support for idempotent form submissions to maintain parity with
`<a>`-initiated Visits.

These changes re-use the existent `Navigator.getActionForFormSubmission`
function to determine the value for the `VisitOptions.action` options.

[#231]: #231

Author: seanpdoyle

src/core/drive/navigator.ts

@@ -92,8 +92,9 @@ export class Navigator {
           this.view.clearSnapshotCache()
         }
 
+        const action = this.getActionForFormSubmission(formSubmission)
         const { statusCode } = fetchResponse
-        const visitOptions = { response: { statusCode, responseHTML } }
+        const visitOptions = { action, response: { statusCode, responseHTML } }
         this.proposeVisit(fetchResponse.location, visitOptions)
       }
     }

src/tests/fixtures/navigation.html

@@ -37,6 +37,18 @@ <h1>Navigation</h1>
       <p><a id="same-origin-replace-link" href="/src/tests/fixtures/one.html" data-turbo-action="replace">Same-origin data-turbo-action=replace link</a></p>
       <p><form id="same-origin-replace-form-get" action="/src/tests/fixtures/one.html" data-turbo-action="replace"><button>Same-origin data-turbo-action=replace form</button></form></p>
       <p><form id="same-origin-replace-form-submitter-get" action="/src/tests/fixtures/one.html"><button data-turbo-action="replace">Same-origin data-turbo-action=replace form</button></form></p>
+      <p>
+        <form id="same-origin-replace-form-post" method="post" action="/__turbo/redirect" data-turbo-action="replace">
+          <input type="hidden" name="path" value="/src/tests/fixtures/one.html">
+          <button>Same-origin form[method="post"][data-turbo-action=replace]</button>
+        </form>
+      </p>
+      <p>
+        <form id="same-origin-replace-form-submitter-post" method="post" action="/__turbo/redirect">
+          <input type="hidden" name="path" value="/src/tests/fixtures/one.html">
+          <button data-turbo-action="replace">Same-origin form[method="post"] button[data-turbo-action=replace]</button>
+        </form>
+      </p>
       <p><a id="same-origin-false-link" href="/src/tests/fixtures/one.html" data-turbo="false">Same-origin data-turbo=false link</a></p>
       <p data-turbo="false"><a id="same-origin-unannotated-link-inside-false-container" href="/src/tests/fixtures/one.html">Same-origin unannotated link inside data-turbo=false container</a></p>
       <p data-turbo="false"><a id="same-origin-true-link-inside-false-container" href="/src/tests/fixtures/one.html" data-turbo="true">Same-origin data-turbo=true link inside data-turbo=false container</a></p>

src/tests/functional/navigation_tests.ts

@@ -77,6 +77,20 @@ export class NavigationTests extends TurboDriveTestCase {
     this.assert.equal(await this.visitAction, "replace")
   }
 
+  async "test following a same-origin POST form[data-turbo-action=replace]"() {
+    this.clickSelector("#same-origin-replace-form-post button")
+    await this.nextBody
+    this.assert.equal(await this.pathname, "/src/tests/fixtures/one.html")
+    this.assert.equal(await this.visitAction, "replace")
+  }
+
+  async "test following a same-origin POST form button[data-turbo-action=replace]"() {
+    this.clickSelector("#same-origin-replace-form-submitter-post button")
+    await this.nextBody
+    this.assert.equal(await this.pathname, "/src/tests/fixtures/one.html")
+    this.assert.equal(await this.visitAction, "replace")
+  }
+
   async "test following a same-origin data-turbo=false link"() {
     this.clickSelector("#same-origin-false-link")
     await this.nextBody