diff --git a/scripts/run-tests.sh b/scripts/run-tests.sh
index 740ed30..c9f164e 100644
--- a/scripts/run-tests.sh
+++ b/scripts/run-tests.sh
@@ -7,7 +7,7 @@ printFileFailedTest () {
 TESTS_FAILED=false
 
 # all these tests must pass compilation
-for FILE in $(ls test/**/*.pass.spec.ts)
+for FILE in $(ls test/**/*.spec.ts)
 do
   tsc --noEmit $FILE > /dev/null
   if [ $? -ne 0 ]; then
@@ -16,16 +16,6 @@ do
   fi
 done
 
-# each of these tests must fail compilation
-for FILE in $(ls test/**/*.fail.spec.ts)
-do
-  tsc --noEmit $FILE > /dev/null
-  if [ $? -eq 0 ]; then
-    TESTS_FAILED=true
-    printFileFailedTest $FILE
-  fi
-done
-
 if $TESTS_FAILED; then
   exit 1
 else
diff --git a/test/control-std-union-without-xor/has-key-not-of-T-nor-of-U.fail.spec.ts b/test/control-std-union-without-xor/has-key-not-of-T-nor-of-U.fail.spec.ts
deleted file mode 100644
index 37bc2cc..0000000
--- a/test/control-std-union-without-xor/has-key-not-of-T-nor-of-U.fail.spec.ts
+++ /dev/null
@@ -1,3 +0,0 @@
-import { A_OR_B } from './setup'
-
-const test: A_OR_B = { lel: '' } // rejected
diff --git a/test/control-std-union-without-xor/has-key-not-of-T-nor-of-U.spec.ts b/test/control-std-union-without-xor/has-key-not-of-T-nor-of-U.spec.ts
new file mode 100644
index 0000000..042e6ef
--- /dev/null
+++ b/test/control-std-union-without-xor/has-key-not-of-T-nor-of-U.spec.ts
@@ -0,0 +1,4 @@
+import { A_OR_B } from './setup'
+
+// @ts-expect-error
+const test: A_OR_B = { lel: '' }
\ No newline at end of file
diff --git a/test/control-std-union-without-xor/has-key-of-T-and-extra-random-key.fail.spec.ts b/test/control-std-union-without-xor/has-key-of-T-and-extra-random-key.fail.spec.ts
deleted file mode 100644
index edf25d9..0000000
--- a/test/control-std-union-without-xor/has-key-of-T-and-extra-random-key.fail.spec.ts
+++ /dev/null
@@ -1,3 +0,0 @@
-import { A_OR_B } from './setup'
-
-const test: A_OR_B = {a: '', lel: '' } // rejected
diff --git a/test/control-std-union-without-xor/has-key-of-T-and-extra-random-key.spec.ts b/test/control-std-union-without-xor/has-key-of-T-and-extra-random-key.spec.ts
new file mode 100644
index 0000000..8d25722
--- /dev/null
+++ b/test/control-std-union-without-xor/has-key-of-T-and-extra-random-key.spec.ts
@@ -0,0 +1,4 @@
+import { A_OR_B } from './setup'
+
+// @ts-expect-error
+const test: A_OR_B = {a: '', lel: '' }
diff --git a/test/control-std-union-without-xor/has-key-of-T-and-key-of-U.pass.spec.ts b/test/control-std-union-without-xor/has-key-of-T-and-key-of-U.spec.ts
similarity index 100%
rename from test/control-std-union-without-xor/has-key-of-T-and-key-of-U.pass.spec.ts
rename to test/control-std-union-without-xor/has-key-of-T-and-key-of-U.spec.ts
diff --git a/test/control-std-union-without-xor/has-keys-of-T.pass.spec.ts b/test/control-std-union-without-xor/has-keys-of-T.spec.ts
similarity index 100%
rename from test/control-std-union-without-xor/has-keys-of-T.pass.spec.ts
rename to test/control-std-union-without-xor/has-keys-of-T.spec.ts
diff --git a/test/control-std-union-without-xor/has-keys-of-U.pass.spec.ts b/test/control-std-union-without-xor/has-keys-of-U.spec.ts
similarity index 100%
rename from test/control-std-union-without-xor/has-keys-of-U.pass.spec.ts
rename to test/control-std-union-without-xor/has-keys-of-U.spec.ts
diff --git a/test/control-std-union-without-xor/has-no-keys.fail.spec.ts b/test/control-std-union-without-xor/has-no-keys.fail.spec.ts
deleted file mode 100644
index 7cfb2fd..0000000
--- a/test/control-std-union-without-xor/has-no-keys.fail.spec.ts
+++ /dev/null
@@ -1,3 +0,0 @@
-import { A_OR_B } from './setup'
-
-const test: A_OR_B = {} // rejected
diff --git a/test/control-std-union-without-xor/has-no-keys.spec.ts b/test/control-std-union-without-xor/has-no-keys.spec.ts
new file mode 100644
index 0000000..2c4bbee
--- /dev/null
+++ b/test/control-std-union-without-xor/has-no-keys.spec.ts
@@ -0,0 +1,4 @@
+import { A_OR_B } from './setup'
+
+// @ts-expect-error
+const test: A_OR_B = {}
diff --git a/test/multiple-xored-types/has-keys-of-A-and-C.fail.spec.ts b/test/multiple-xored-types/has-keys-of-A-and-C.fail.spec.ts
deleted file mode 100644
index 3fb266e..0000000
--- a/test/multiple-xored-types/has-keys-of-A-and-C.fail.spec.ts
+++ /dev/null
@@ -1,3 +0,0 @@
-import { A_XOR_B_XOR_C } from './setup'
-
-const test: A_XOR_B_XOR_C = { a: '', c: '' }  // rejected
diff --git a/test/multiple-xored-types/has-keys-of-A-and-C.spec.ts b/test/multiple-xored-types/has-keys-of-A-and-C.spec.ts
new file mode 100644
index 0000000..ea1192c
--- /dev/null
+++ b/test/multiple-xored-types/has-keys-of-A-and-C.spec.ts
@@ -0,0 +1,4 @@
+import { A_XOR_B_XOR_C } from './setup'
+
+// @ts-expect-error
+const test: A_XOR_B_XOR_C = { a: '', c: '' }
diff --git a/test/multiple-xored-types/has-keys-of-A.pass.spec.ts b/test/multiple-xored-types/has-keys-of-A.spec.ts
similarity index 100%
rename from test/multiple-xored-types/has-keys-of-A.pass.spec.ts
rename to test/multiple-xored-types/has-keys-of-A.spec.ts
diff --git a/test/multiple-xored-types/has-keys-of-B.pass.spec.ts b/test/multiple-xored-types/has-keys-of-B.spec.ts
similarity index 100%
rename from test/multiple-xored-types/has-keys-of-B.pass.spec.ts
rename to test/multiple-xored-types/has-keys-of-B.spec.ts
diff --git a/test/multiple-xored-types/has-keys-of-C.pass.spec.ts b/test/multiple-xored-types/has-keys-of-C.spec.ts
similarity index 100%
rename from test/multiple-xored-types/has-keys-of-C.pass.spec.ts
rename to test/multiple-xored-types/has-keys-of-C.spec.ts
diff --git a/test/multiple-xored-types/has-no-keys.fail.spec.ts b/test/multiple-xored-types/has-no-keys.fail.spec.ts
deleted file mode 100644
index 6dede9c..0000000
--- a/test/multiple-xored-types/has-no-keys.fail.spec.ts
+++ /dev/null
@@ -1,3 +0,0 @@
-import { A_XOR_B_XOR_C } from './setup'
-
-const test: A_XOR_B_XOR_C = {} // rejected
diff --git a/test/multiple-xored-types/has-no-keys.spec.ts b/test/multiple-xored-types/has-no-keys.spec.ts
new file mode 100644
index 0000000..8455662
--- /dev/null
+++ b/test/multiple-xored-types/has-no-keys.spec.ts
@@ -0,0 +1,4 @@
+import { A_XOR_B_XOR_C } from './setup'
+
+// @ts-expect-error
+const test: A_XOR_B_XOR_C = {}
diff --git a/test/shared-and-xored-members/doesnt-have-rain-or-snow.fail.spec.ts b/test/shared-and-xored-members/doesnt-have-rain-or-snow.spec.ts
similarity index 75%
rename from test/shared-and-xored-members/doesnt-have-rain-or-snow.fail.spec.ts
rename to test/shared-and-xored-members/doesnt-have-rain-or-snow.spec.ts
index 3ff3794..49861b3 100644
--- a/test/shared-and-xored-members/doesnt-have-rain-or-snow.fail.spec.ts
+++ b/test/shared-and-xored-members/doesnt-have-rain-or-snow.spec.ts
@@ -3,5 +3,6 @@ import { WeatherForecast } from './setup'
 const test: WeatherForecast = {
   id: 123456,
   station: 'Acropolis Weather Reporter',
-  lel: { '1h': 1 }, // rejected
+  // @ts-expect-error
+  lel: { '1h': 1 },
 }
diff --git a/test/shared-and-xored-members/has-rain-and-snow-with-correct-keys.fail.spec.ts b/test/shared-and-xored-members/has-rain-and-snow-with-correct-keys.spec.ts
similarity index 78%
rename from test/shared-and-xored-members/has-rain-and-snow-with-correct-keys.fail.spec.ts
rename to test/shared-and-xored-members/has-rain-and-snow-with-correct-keys.spec.ts
index 2af57e5..776672b 100644
--- a/test/shared-and-xored-members/has-rain-and-snow-with-correct-keys.fail.spec.ts
+++ b/test/shared-and-xored-members/has-rain-and-snow-with-correct-keys.spec.ts
@@ -1,8 +1,9 @@
 import { WeatherForecast } from './setup'
 
+// @ts-expect-error
 const test: WeatherForecast = {
   id: 123456,
   station: 'Acropolis Weather Reporter',
   rain: { '1h': 1 },
-  snow: { '3h': 3 }, // rejected
+  snow: { '3h': 3 },
 }
diff --git a/test/shared-and-xored-members/has-rain-with-corect-key-and-random-extra-key.fail.spec.ts b/test/shared-and-xored-members/has-rain-with-both-xored-keys.spec.ts
similarity index 71%
rename from test/shared-and-xored-members/has-rain-with-corect-key-and-random-extra-key.fail.spec.ts
rename to test/shared-and-xored-members/has-rain-with-both-xored-keys.spec.ts
index ec8749b..cd28c5e 100644
--- a/test/shared-and-xored-members/has-rain-with-corect-key-and-random-extra-key.fail.spec.ts
+++ b/test/shared-and-xored-members/has-rain-with-both-xored-keys.spec.ts
@@ -1,7 +1,8 @@
 import { WeatherForecast } from './setup'
 
 const test: WeatherForecast = {
-  id: 123456,
   station: 'Acropolis Weather Reporter',
-  rain: { '1h': 1, lel: 'rofl' }, // fail
+  id: 123456,
+  // @ts-expect-error
+  rain: { '1h': 1, '3h': 3 },
 }
diff --git a/test/shared-and-xored-members/has-rain-with-corect-key-and-random-extra-key.spec.ts b/test/shared-and-xored-members/has-rain-with-corect-key-and-random-extra-key.spec.ts
new file mode 100644
index 0000000..2366422
--- /dev/null
+++ b/test/shared-and-xored-members/has-rain-with-corect-key-and-random-extra-key.spec.ts
@@ -0,0 +1,8 @@
+import { WeatherForecast } from './setup'
+
+const test: WeatherForecast = {
+  id: 123456,
+  station: 'Acropolis Weather Reporter',
+  // @ts-expect-error
+  rain: { '1h': 1, lel: 'rofl' },
+}
diff --git a/test/shared-and-xored-members/has-rain-with-correct-key.pass.spec.ts b/test/shared-and-xored-members/has-rain-with-correct-key.spec.ts
similarity index 100%
rename from test/shared-and-xored-members/has-rain-with-correct-key.pass.spec.ts
rename to test/shared-and-xored-members/has-rain-with-correct-key.spec.ts
diff --git a/test/shared-and-xored-members/has-rain-with-no-keys.fail.spec.ts b/test/shared-and-xored-members/has-rain-with-no-keys.spec.ts
similarity index 79%
rename from test/shared-and-xored-members/has-rain-with-no-keys.fail.spec.ts
rename to test/shared-and-xored-members/has-rain-with-no-keys.spec.ts
index 2056a24..7014706 100644
--- a/test/shared-and-xored-members/has-rain-with-no-keys.fail.spec.ts
+++ b/test/shared-and-xored-members/has-rain-with-no-keys.spec.ts
@@ -3,5 +3,6 @@ import { WeatherForecast } from './setup'
 const test: WeatherForecast = {
   id: 123456,
   station: 'Acropolis Weather Reporter',
-  rain: {}, // rejected
+  // @ts-expect-error
+  rain: {},
 }
diff --git a/test/shared-and-xored-members/has-rain-with-random-key.fail.spec.ts b/test/shared-and-xored-members/has-rain-with-random-key.fail.spec.ts
deleted file mode 100644
index 7f8f41e..0000000
--- a/test/shared-and-xored-members/has-rain-with-random-key.fail.spec.ts
+++ /dev/null
@@ -1,7 +0,0 @@
-import { WeatherForecast } from './setup'
-
-const test: WeatherForecast = {
-  id: 123456,
-  station: 'Acropolis Weather Reporter',
-  rain: { '2h': 1 }, // rejected
-}
diff --git a/test/shared-and-xored-members/has-rain-with-both-xored-keys.fail.spec.ts b/test/shared-and-xored-members/has-rain-with-random-key.spec.ts
similarity index 75%
rename from test/shared-and-xored-members/has-rain-with-both-xored-keys.fail.spec.ts
rename to test/shared-and-xored-members/has-rain-with-random-key.spec.ts
index ac5a00a..c904a0a 100644
--- a/test/shared-and-xored-members/has-rain-with-both-xored-keys.fail.spec.ts
+++ b/test/shared-and-xored-members/has-rain-with-random-key.spec.ts
@@ -1,7 +1,8 @@
 import { WeatherForecast } from './setup'
 
 const test: WeatherForecast = {
-  station: 'Acropolis Weather Reporter',
   id: 123456,
-  rain: { '1h': 1, '3h': 3 }, // rejected
+  station: 'Acropolis Weather Reporter',
+  // @ts-expect-error
+  rain: { '2h': 1 },
 }
diff --git a/test/single-member-objects/has-key-not-of-T-nor-of-U.fail.spec.ts b/test/single-member-objects/has-key-not-of-T-nor-of-U.fail.spec.ts
deleted file mode 100644
index 7628b3b..0000000
--- a/test/single-member-objects/has-key-not-of-T-nor-of-U.fail.spec.ts
+++ /dev/null
@@ -1,3 +0,0 @@
-import { A_XOR_B } from './setup'
-
-const test: A_XOR_B = { lel: '' } // rejected
diff --git a/test/single-member-objects/has-key-not-of-T-nor-of-U.spec.ts b/test/single-member-objects/has-key-not-of-T-nor-of-U.spec.ts
new file mode 100644
index 0000000..39fd074
--- /dev/null
+++ b/test/single-member-objects/has-key-not-of-T-nor-of-U.spec.ts
@@ -0,0 +1,4 @@
+import { A_XOR_B } from './setup'
+
+// @ts-expect-error
+const test: A_XOR_B = { lel: '' }
diff --git a/test/single-member-objects/has-key-of-T-and-extra-random-key.fail.spec.ts b/test/single-member-objects/has-key-of-T-and-extra-random-key.fail.spec.ts
deleted file mode 100644
index 9725197..0000000
--- a/test/single-member-objects/has-key-of-T-and-extra-random-key.fail.spec.ts
+++ /dev/null
@@ -1,3 +0,0 @@
-import { A_XOR_B } from './setup'
-
-const test: A_XOR_B = {a: '', lel: '' } // rejected
diff --git a/test/single-member-objects/has-key-of-T-and-extra-random-key.spec.ts b/test/single-member-objects/has-key-of-T-and-extra-random-key.spec.ts
new file mode 100644
index 0000000..ce30e06
--- /dev/null
+++ b/test/single-member-objects/has-key-of-T-and-extra-random-key.spec.ts
@@ -0,0 +1,4 @@
+import { A_XOR_B } from './setup'
+
+// @ts-expect-error
+const test: A_XOR_B = {a: '', lel: '' }
diff --git a/test/single-member-objects/has-key-of-T-and-key-of-U.fail.spec.ts b/test/single-member-objects/has-key-of-T-and-key-of-U.fail.spec.ts
deleted file mode 100644
index 21cb801..0000000
--- a/test/single-member-objects/has-key-of-T-and-key-of-U.fail.spec.ts
+++ /dev/null
@@ -1,3 +0,0 @@
-import { A_XOR_B } from './setup'
-
-const test: A_XOR_B = { a: '', b: '' } // rejected
diff --git a/test/single-member-objects/has-key-of-T-and-key-of-U.spec.ts b/test/single-member-objects/has-key-of-T-and-key-of-U.spec.ts
new file mode 100644
index 0000000..3750d63
--- /dev/null
+++ b/test/single-member-objects/has-key-of-T-and-key-of-U.spec.ts
@@ -0,0 +1,4 @@
+import { A_XOR_B } from './setup'
+
+// @ts-expect-error
+const test: A_XOR_B = { a: '', b: '' }
diff --git a/test/single-member-objects/has-keys-of-T.pass.spec.ts b/test/single-member-objects/has-keys-of-T.spec.ts
similarity index 100%
rename from test/single-member-objects/has-keys-of-T.pass.spec.ts
rename to test/single-member-objects/has-keys-of-T.spec.ts
diff --git a/test/single-member-objects/has-keys-of-U.pass.spec.ts b/test/single-member-objects/has-keys-of-U.spec.ts
similarity index 100%
rename from test/single-member-objects/has-keys-of-U.pass.spec.ts
rename to test/single-member-objects/has-keys-of-U.spec.ts
diff --git a/test/single-member-objects/has-no-keys.fail.spec.ts b/test/single-member-objects/has-no-keys.fail.spec.ts
deleted file mode 100644
index c3c7d78..0000000
--- a/test/single-member-objects/has-no-keys.fail.spec.ts
+++ /dev/null
@@ -1,3 +0,0 @@
-import { A_XOR_B } from './setup'
-
-const test: A_XOR_B = {} // rejected
diff --git a/test/single-member-objects/has-no-keys.spec.ts b/test/single-member-objects/has-no-keys.spec.ts
new file mode 100644
index 0000000..c062576
--- /dev/null
+++ b/test/single-member-objects/has-no-keys.spec.ts
@@ -0,0 +1,4 @@
+import { A_XOR_B } from './setup'
+
+// @ts-expect-error
+const test: A_XOR_B = {}