Revert "pipeline: Drop expectation files"

This reverts commit cbe35e3e72a267a76a00cc479a177979c8cec357.

Reason for revert: b/331280031

Original change's description:
> pipeline: Drop expectation files
>
> Change-Id: If3764c5662a2da05e3ddf8293e30769f1d259711
> Reviewed-on: https://pigweed-review.googlesource.com/c/infra/recipes/+/199611
> Presubmit-Verified: CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com>
> Pigweed-Auto-Submit: Rob Mohr <mohrr@google.com>
> Commit-Queue: Auto-Submit <auto-submit@pigweed-service-accounts.iam.gserviceaccount.com>
> Reviewed-by: Ted Pudlik <tpudlik@google.com>

TBR=mohrr@google.com,pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com,tpudlik@google.com,auto-submit@pigweed-service-accounts.iam.gserviceaccount.com

Change-Id: I602b1c7a330f0c5f63f3decd2a67f7a972340d95
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: b/331280031
Reviewed-on: https://pigweed-review.googlesource.com/c/infra/recipes/+/199930
Pigweed-Auto-Submit: Rob Mohr <mohrr@google.com>
Reviewed-by: William Abajian <williamabajian@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed-service-accounts.iam.gserviceaccount.com>
diff --git a/recipe_modules/pipeline/tests/full.expected/empty.json b/recipe_modules/pipeline/tests/full.expected/empty.json
new file mode 100644
index 0000000..7d97243
--- /dev/null
+++ b/recipe_modules/pipeline/tests/full.expected/empty.json
@@ -0,0 +1,9 @@
+[
+  {
+    "cmd": [],
+    "name": "not in pipeline"
+  },
+  {
+    "name": "$result"
+  }
+]
\ No newline at end of file
diff --git a/recipe_modules/pipeline/tests/full.expected/round_0.json b/recipe_modules/pipeline/tests/full.expected/round_0.json
new file mode 100644
index 0000000..cc68ad8
--- /dev/null
+++ b/recipe_modules/pipeline/tests/full.expected/round_0.json
@@ -0,0 +1,17 @@
+[
+  {
+    "cmd": [],
+    "name": "in pipeline"
+  },
+  {
+    "cmd": [],
+    "name": "round 0"
+  },
+  {
+    "cmd": [],
+    "name": "0 previous builds"
+  },
+  {
+    "name": "$result"
+  }
+]
\ No newline at end of file
diff --git a/recipe_modules/pipeline/tests/full.expected/round_1.json b/recipe_modules/pipeline/tests/full.expected/round_1.json
new file mode 100644
index 0000000..b0e3d4e
--- /dev/null
+++ b/recipe_modules/pipeline/tests/full.expected/round_1.json
@@ -0,0 +1,21 @@
+[
+  {
+    "cmd": [],
+    "name": "in pipeline"
+  },
+  {
+    "cmd": [],
+    "name": "round 1"
+  },
+  {
+    "cmd": [],
+    "name": "1 previous builds"
+  },
+  {
+    "cmd": [],
+    "name": "previous build 123"
+  },
+  {
+    "name": "$result"
+  }
+]
\ No newline at end of file
diff --git a/recipe_modules/pipeline/tests/full.expected/round_4.json b/recipe_modules/pipeline/tests/full.expected/round_4.json
new file mode 100644
index 0000000..90cad80
--- /dev/null
+++ b/recipe_modules/pipeline/tests/full.expected/round_4.json
@@ -0,0 +1,29 @@
+[
+  {
+    "cmd": [],
+    "name": "in pipeline"
+  },
+  {
+    "cmd": [],
+    "name": "round 4"
+  },
+  {
+    "cmd": [],
+    "name": "3 previous builds"
+  },
+  {
+    "cmd": [],
+    "name": "previous build 123"
+  },
+  {
+    "cmd": [],
+    "name": "previous build 456"
+  },
+  {
+    "cmd": [],
+    "name": "previous build 789"
+  },
+  {
+    "name": "$result"
+  }
+]
\ No newline at end of file
diff --git a/recipe_modules/pipeline/tests/full.py b/recipe_modules/pipeline/tests/full.py
index 4817c4b..ec7948d 100644
--- a/recipe_modules/pipeline/tests/full.py
+++ b/recipe_modules/pipeline/tests/full.py
@@ -40,9 +40,6 @@
     def ran(x):
         return api.post_process(post_process.MustRun, x)
 
-    def drop():
-        return api.post_process(post_process.DropExpectation)
-
     yield api.test('nopipeline') + ran('not in pipeline')
 
     yield (
@@ -51,7 +48,6 @@
         + ran('in pipeline')
         + ran('round 0')
         + ran('0 previous builds')
-        + drop()
     )
 
     yield (
@@ -61,7 +57,6 @@
         + ran('round 1')
         + ran('1 previous builds')
         + ran('previous build 123')
-        + drop()
     )
 
     yield (
@@ -73,7 +68,6 @@
         + ran('previous build 123')
         + ran('previous build 456')
         + ran('previous build 789')
-        + drop()
     )
 
-    yield api.test('empty') + ran('not in pipeline') + drop()
+    yield api.test('empty')