diff --git a/test/README.md b/test/README.md
index b102aa14a9..662ed1bcd6 100644
--- a/test/README.md
+++ b/test/README.md
@@ -155,7 +155,7 @@ the behaviour of calling it as the `rv` value of MatchSelectorKeys(`rv`, `keys`)
 depends on its `Input`, `DecimalPlaces` and `FailsSelect` values.
 
 - If `FailsSelect` is `true`,
-  calling the method will emit a _Message Function Error_
+  calling the method will emit a _Bad Operand_ error
   and not return any value.
 - If the `Input` is 1 and `DecimalPlaces` is 1,
   the method will return some slice of the list « `'1.0'`, `'1'` »,
@@ -185,7 +185,7 @@ rather than being concatenated into a single string.
 
 If `FailsFormat` is `true`,
 attempting to format the _placeholder_ to any formatting target will
-emit a _Message Function Error_.
+emit a _Bad Operand_ error.
 
 ### `:test:select`
 
diff --git a/test/schemas/v0/tests.schema.json b/test/schemas/v0/tests.schema.json
index cf8e821947..d0215dae33 100644
--- a/test/schemas/v0/tests.schema.json
+++ b/test/schemas/v0/tests.schema.json
@@ -382,10 +382,7 @@
     },
     "expErrors": {
       "description": "The runtime errors expected to be emitted when formatting the message. If expErrors is either absent or empty, the message must be formatted without errors.",
-      "type": [
-        "array",
-        "boolean"
-      ],
+      "type": "array",
       "items": {
         "type": "object",
         "additionalProperties": false,
diff --git a/test/tests/fallback.json b/test/tests/fallback.json
index abf062e1c3..8c342923d7 100644
--- a/test/tests/fallback.json
+++ b/test/tests/fallback.json
@@ -4,52 +4,59 @@
   "description": "Test cases for fallback behaviour.",
   "defaultTestProperties": {
     "bidiIsolation": "none",
-    "locale": "en-US",
-    "expErrors": true
+    "locale": "en-US"
   },
   "tests": [
     {
       "description": "function with unquoted literal operand",
       "src": "{42 :test:function fails=format}",
       "exp": "{|42|}",
-      "expParts": [{ "type": "fallback", "source": "|42|" }]
+      "expParts": [{ "type": "fallback", "source": "|42|" }],
+      "expErrors": [{ "type": "bad-operand" }]
     },
     {
       "description": "function with quoted literal operand",
       "src": "{|C:\\\\| :test:function fails=format}",
-      "exp": "{|C:\\\\|}"
+      "exp": "{|C:\\\\|}",
+      "expErrors": [{ "type": "bad-operand" }]
     },
     {
       "description": "unannotated implicit input variable",
       "src": "{$var}",
-      "exp": "{$var}"
+      "exp": "{$var}",
+      "expErrors": [{ "type": "unresolved-variable" }]
     },
     {
       "description": "annotated implicit input variable",
       "src": "{$var :number}",
       "exp": "{$var}",
-      "expParts": [{ "type": "fallback", "source": "$var" }]
+      "expParts": [{ "type": "fallback", "source": "$var" }],
+      "expErrors": [{ "type": "unresolved-variable" }, { "type": "bad-operand" }]
     },
     {
       "description": "local variable with unknown function in declaration",
       "src": ".local $var = {|val| :test:undefined} {{{$var}}}",
-      "exp": "{$var}"
+      "exp": "{$var}",
+      "expErrors": [{ "type": "unknown-function" }]
     },
     {
       "description": "function with local variable operand with unknown function in declaration",
       "src": ".local $var = {|val| :test:undefined} {{{$var :test:function}}}",
-      "exp": "{$var}"
+      "exp": "{$var}",
+      "expErrors": [{ "type": "unknown-function" }, { "type": "bad-operand" }]
     },
     {
       "description": "local variable with unknown function in placeholder",
       "src": ".local $var = {|val|} {{{$var :test:undefined}}}",
-      "exp": "{$var}"
+      "exp": "{$var}",
+      "expErrors": [{ "type": "unknown-function" }]
     },
     {
       "description": "function with no operand",
       "src": "{:test:undefined}",
       "exp": "{:test:undefined}",
-      "expParts": [{ "type": "fallback", "source": ":test:undefined" }]
+      "expParts": [{ "type": "fallback", "source": ":test:undefined" }],
+      "expErrors": [{ "type": "unknown-function" }]
     }
   ]
 }
diff --git a/test/tests/functions/currency.json b/test/tests/functions/currency.json
index ea1d8aee62..593ec54863 100644
--- a/test/tests/functions/currency.json
+++ b/test/tests/functions/currency.json
@@ -4,7 +4,8 @@
   "description": "The built-in formatter and selector for currencies.",
   "defaultTestProperties": {
     "bidiIsolation": "none",
-    "locale": "en-US"
+    "locale": "en-US",
+    "expErrors": []
   },
   "tests": [
     {
@@ -24,33 +25,26 @@
       "expErrors": [{ "type": "bad-operand" }]
     },
     {
-      "src": "{42 :currency currency=EUR}",
-      "expErrors": false
+      "src": "{42 :currency currency=EUR}"
     },
     {
-      "src": ".local $n = {42 :number} {{{$n :currency currency=EUR}}}",
-      "expErrors": false
+      "src": ".local $n = {42 :number} {{{$n :currency currency=EUR}}}"
     },
     {
-      "src": ".local $n = {42 :integer} {{{$n :currency currency=EUR}}}",
-      "expErrors": false
+      "src": ".local $n = {42 :integer} {{{$n :currency currency=EUR}}}"
     },
     {
-      "src": ".local $n = {42 :currency currency=EUR} {{{$n :currency}}}",
-      "expErrors": false
+      "src": ".local $n = {42 :currency currency=EUR} {{{$n :currency}}}"
     },
     {
-      "src": "{42 :currency currency=EUR fractionDigits=auto}",
-      "expErrors": false
+      "src": "{42 :currency currency=EUR fractionDigits=auto}"
     },
     {
-      "src": "{42 :currency currency=EUR fractionDigits=2}",
-      "expErrors": false
+      "src": "{42 :currency currency=EUR fractionDigits=2}"
     },
     {
       "src": "{$x :currency currency=EUR}",
-      "params": [{ "name": "x", "value": 41 }],
-      "expErrors": false
+      "params": [{ "name": "x", "value": 41 }]
     },
     {
       "src": ".local $n = {42 :currency currency=EUR} .match $n * {{other}}",
diff --git a/test/tests/functions/date.json b/test/tests/functions/date.json
index c20b69a1bf..5dd1378f9d 100644
--- a/test/tests/functions/date.json
+++ b/test/tests/functions/date.json
@@ -5,7 +5,7 @@
   "defaultTestProperties": {
     "bidiIsolation": "none",
     "locale": "en-US",
-    "expErrors": false
+    "expErrors": []
   },
   "tests": [
     {
diff --git a/test/tests/functions/datetime.json b/test/tests/functions/datetime.json
index 1d45518290..d7e6cbef55 100644
--- a/test/tests/functions/datetime.json
+++ b/test/tests/functions/datetime.json
@@ -5,7 +5,7 @@
   "defaultTestProperties": {
     "bidiIsolation": "none",
     "locale": "en-US",
-    "expErrors": false
+    "expErrors": []
   },
   "tests": [
     {
diff --git a/test/tests/functions/time.json b/test/tests/functions/time.json
index 56aab3e3fb..140902bb4c 100644
--- a/test/tests/functions/time.json
+++ b/test/tests/functions/time.json
@@ -5,7 +5,7 @@
   "defaultTestProperties": {
     "bidiIsolation": "none",
     "locale": "en-US",
-    "expErrors": false
+    "expErrors": []
   },
   "tests": [
     {