diff --git a/src/main/java/org/cactoos/BiProc.java b/src/main/java/org/cactoos/BiProc.java
index fceb567d77..8ffeafc3d4 100644
--- a/src/main/java/org/cactoos/BiProc.java
+++ b/src/main/java/org/cactoos/BiProc.java
@@ -39,6 +39,10 @@
  * @param <X> Type of input
  * @param <Y> Type of input
  * @since 0.20
+ * @todo #1445:30min Introduce BiProcOf on the model of ProcOf, FuncOf, etc
+ *  with constructors taking Func, BiFunc, Proc and BiProc as primary.
+ *  Add tests similar to those of ProcOfTest, FuncOfTest, etc to fully cover
+ *  the implementation. Use it where needed, for example in AndWithIndexTest.
  */
 public interface BiProc<X, Y> {
 
diff --git a/src/main/java/org/cactoos/proc/ForEach.java b/src/main/java/org/cactoos/proc/ForEach.java
index 67d2fa07f4..0d7a5db3e1 100644
--- a/src/main/java/org/cactoos/proc/ForEach.java
+++ b/src/main/java/org/cactoos/proc/ForEach.java
@@ -23,7 +23,6 @@
  */
 package org.cactoos.proc;
 
-import org.cactoos.Func;
 import org.cactoos.Proc;
 import org.cactoos.func.FuncOf;
 import org.cactoos.scalar.And;
@@ -47,7 +46,7 @@
  * <p>
  * There is no thread-safety guarantee.
  *
- * @param <X> The type to itetare over
+ * @param <X> The type to iterate over
  * @since 1.0
  */
 public final class ForEach<X> implements Proc<Iterable<X>> {
@@ -55,7 +54,7 @@ public final class ForEach<X> implements Proc<Iterable<X>> {
     /**
      * The proc.
      */
-    private final Func<X, Boolean> func;
+    private final Proc<X> proc;
 
     /**
      * Ctor.
@@ -63,15 +62,13 @@ public final class ForEach<X> implements Proc<Iterable<X>> {
      * @param proc The proc to execute
      */
     public ForEach(final Proc<X> proc) {
-        this.func = new FuncOf<>(
-            proc, true
-        );
+        this.proc = proc;
     }
 
     @Override
     public void exec(final Iterable<X> input) throws Exception {
         new And(
-            this.func, input
+            new FuncOf<>(this.proc, true), input
         ).value();
     }
 
diff --git a/src/main/java/org/cactoos/proc/ForEachInThreads.java b/src/main/java/org/cactoos/proc/ForEachInThreads.java
index 37dd70b1bc..8698463318 100644
--- a/src/main/java/org/cactoos/proc/ForEachInThreads.java
+++ b/src/main/java/org/cactoos/proc/ForEachInThreads.java
@@ -23,7 +23,6 @@
  */
 package org.cactoos.proc;
 
-import org.cactoos.Func;
 import org.cactoos.Proc;
 import org.cactoos.func.FuncOf;
 import org.cactoos.scalar.AndInThreads;
@@ -49,7 +48,7 @@
  * <p>
  * There is no thread-safety guarantee.
  *
- * @param <X> The type to itetare over
+ * @param <X> The type to iterate over
  * @since 1.0
  */
 public final class ForEachInThreads<X> implements Proc<Iterable<X>> {
@@ -57,7 +56,7 @@ public final class ForEachInThreads<X> implements Proc<Iterable<X>> {
     /**
      * The proc.
      */
-    private final Func<X, Boolean> func;
+    private final Proc<X> proc;
 
     /**
      * Ctor.
@@ -65,15 +64,13 @@ public final class ForEachInThreads<X> implements Proc<Iterable<X>> {
      * @param proc The proc to execute
      */
     public ForEachInThreads(final Proc<X> proc) {
-        this.func = new FuncOf<>(
-            proc, true
-        );
+        this.proc = proc;
     }
 
     @Override
     public void exec(final Iterable<X> input) throws Exception {
         new AndInThreads(
-            this.func, input
+            new FuncOf<>(this.proc, true), input
         ).value();
     }
 
diff --git a/src/main/java/org/cactoos/proc/ForEachWithIndex.java b/src/main/java/org/cactoos/proc/ForEachWithIndex.java
index 725bdc7854..025a13af71 100644
--- a/src/main/java/org/cactoos/proc/ForEachWithIndex.java
+++ b/src/main/java/org/cactoos/proc/ForEachWithIndex.java
@@ -23,10 +23,8 @@
  */
 package org.cactoos.proc;
 
-import org.cactoos.BiFunc;
 import org.cactoos.BiProc;
 import org.cactoos.Proc;
-import org.cactoos.func.BiFuncOf;
 import org.cactoos.scalar.AndWithIndex;
 
 /**
@@ -57,7 +55,7 @@ public final class ForEachWithIndex<X> implements Proc<Iterable<X>> {
     /**
      * The proc.
      */
-    private final BiFunc<X, Integer, Boolean> func;
+    private final BiProc<X, Integer> proc;
 
     /**
      * Ctor.
@@ -65,15 +63,13 @@ public final class ForEachWithIndex<X> implements Proc<Iterable<X>> {
      * @param proc The proc to execute
      */
     public ForEachWithIndex(final BiProc<X, Integer> proc) {
-        this.func = new BiFuncOf<>(
-            proc, true
-        );
+        this.proc = proc;
     }
 
     @Override
     public void exec(final Iterable<X> input) throws Exception {
         new AndWithIndex(
-            this.func, input
+            this.proc, input
         ).value();
     }
 }
diff --git a/src/main/java/org/cactoos/proc/ProcOf.java b/src/main/java/org/cactoos/proc/ProcOf.java
index 8fe9fdca5d..b65248362f 100644
--- a/src/main/java/org/cactoos/proc/ProcOf.java
+++ b/src/main/java/org/cactoos/proc/ProcOf.java
@@ -46,7 +46,11 @@ public final class ProcOf<X> implements Proc<X> {
      * @param fnc The proc
      */
     public ProcOf(final Func<X, ?> fnc) {
-        this((Proc<X>) fnc::apply);
+        this(
+            input -> {
+                fnc.apply(input);
+            }
+        );
     }
 
     /**
diff --git a/src/main/java/org/cactoos/scalar/And.java b/src/main/java/org/cactoos/scalar/And.java
index 8755f8aff4..dd33598d18 100644
--- a/src/main/java/org/cactoos/scalar/And.java
+++ b/src/main/java/org/cactoos/scalar/And.java
@@ -91,7 +91,8 @@ public <X> And(final Func<X, Boolean> func, final X... src) {
     public <X> And(final Func<X, Boolean> func, final Iterable<X> src) {
         this(
             new Mapped<>(
-                item -> (Scalar<Boolean>) () -> func.apply(item), src
+                item -> new ScalarOf<>(() -> func.apply(item)),
+                src
             )
         );
     }
@@ -105,10 +106,21 @@ public <X> And(final Func<X, Boolean> func, final Iterable<X> src) {
      */
     @SafeVarargs
     public <X> And(final X subject, final Func<X, Boolean>... conditions) {
+        this(subject, new IterableOf<>(conditions));
+    }
+
+    /**
+     * Ctor.
+     * @param subject The subject
+     * @param conditions Funcs to map
+     * @param <X> Type of items in the iterable
+     * @since 0.49
+     */
+    public <X> And(final X subject, final Iterable<Func<X, Boolean>> conditions) {
         this(
             new Mapped<>(
-                item -> (Scalar<Boolean>) () -> item.apply(subject),
-                new IterableOf<>(conditions)
+                item -> new ScalarOf<>(() -> item.apply(subject)),
+                conditions
             )
         );
     }
diff --git a/src/main/java/org/cactoos/scalar/AndInThreads.java b/src/main/java/org/cactoos/scalar/AndInThreads.java
index 37d896d1ef..90b226844c 100644
--- a/src/main/java/org/cactoos/scalar/AndInThreads.java
+++ b/src/main/java/org/cactoos/scalar/AndInThreads.java
@@ -92,7 +92,8 @@ public <X> AndInThreads(final Func<X, Boolean> func,
         final Iterable<X> src) {
         this(
             new Mapped<>(
-                item -> (Scalar<Boolean>) () -> func.apply(item), src
+                item -> new ScalarOf<>(() -> func.apply(item)),
+                src
             )
         );
     }
@@ -164,7 +165,8 @@ public <X> AndInThreads(final ExecutorService svc,
         this(
             svc,
             new Mapped<>(
-                item -> (Scalar<Boolean>) () -> func.apply(item), src
+                item -> new ScalarOf<>(() -> func.apply(item)),
+                src
             )
         );
     }
@@ -210,7 +212,7 @@ public Boolean value() throws Exception {
             futures.add(this.service.submit(item::value));
         }
         final boolean result = new And(
-            (Func<Future<Boolean>, Boolean>) Future::get,
+            Future::get,
             futures
         ).value();
         if (this.shut) {
diff --git a/src/main/java/org/cactoos/scalar/AndWithIndex.java b/src/main/java/org/cactoos/scalar/AndWithIndex.java
index a1f9103dc6..7997202872 100644
--- a/src/main/java/org/cactoos/scalar/AndWithIndex.java
+++ b/src/main/java/org/cactoos/scalar/AndWithIndex.java
@@ -29,6 +29,7 @@
 import org.cactoos.Proc;
 import org.cactoos.Scalar;
 import org.cactoos.func.BiFuncOf;
+import org.cactoos.func.FuncOf;
 import org.cactoos.iterable.IterableOf;
 import org.cactoos.iterable.Mapped;
 
@@ -115,8 +116,8 @@ public <X> AndWithIndex(final BiFunc<X, Integer, Boolean> func,
         final Iterable<X> src) {
         this(
             new Mapped<>(
-                item -> (Func<Integer, Boolean>) input
-                    -> func.apply(item, input), src
+                item -> new FuncOf<>(input -> func.apply(item, input)),
+                src
             )
         );
     }
diff --git a/src/main/java/org/cactoos/scalar/Or.java b/src/main/java/org/cactoos/scalar/Or.java
index c3438938ca..fefb1fc8ab 100644
--- a/src/main/java/org/cactoos/scalar/Or.java
+++ b/src/main/java/org/cactoos/scalar/Or.java
@@ -125,7 +125,8 @@ public <X> Or(final Proc<X> proc, final Iterable<X> src) {
     public <X> Or(final Func<X, Boolean> func, final Iterable<X> src) {
         this(
             new Mapped<>(
-                item -> (Scalar<Boolean>) () -> func.apply(item), src
+                item -> new ScalarOf<>(() -> func.apply(item)),
+                src
             )
         );
     }
@@ -140,7 +141,7 @@ public <X> Or(final Func<X, Boolean> func, final Iterable<X> src) {
     public <X> Or(final X subject, final Func<X, Boolean>... conditions) {
         this(
             new Mapped<>(
-                item -> (Scalar<Boolean>) () -> item.apply(subject),
+                item -> new ScalarOf<>(() -> item.apply(subject)),
                 new IterableOf<>(conditions)
             )
         );
diff --git a/src/test/java/org/cactoos/func/BiFuncOfTest.java b/src/test/java/org/cactoos/func/BiFuncOfTest.java
index 566db12587..c67eab3398 100644
--- a/src/test/java/org/cactoos/func/BiFuncOfTest.java
+++ b/src/test/java/org/cactoos/func/BiFuncOfTest.java
@@ -23,21 +23,22 @@
  */
 package org.cactoos.func;
 
-import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicReference;
+import org.cactoos.BiFunc;
 import org.cactoos.proc.ProcOf;
-import org.cactoos.scalar.True;
-import org.hamcrest.core.IsEqual;
+import org.cactoos.scalar.Constant;
+import org.hamcrest.core.IsSame;
 import org.junit.jupiter.api.Test;
 import org.llorllale.cactoos.matchers.Assertion;
-import org.llorllale.cactoos.matchers.IsTrue;
+import org.llorllale.cactoos.matchers.MatcherOf;
 
 /**
  * Test case for {@link BiFuncOf}.
  *
  * @since 0.20
- * @checkstyle JavadocMethodCheck (500 lines)
  * @checkstyle ClassDataAbstractionCouplingCheck (500 lines)
  */
+@SuppressWarnings("PMD.AvoidDuplicateLiterals")
 final class BiFuncOfTest {
 
     @Test
@@ -45,35 +46,65 @@ void convertsFuncIntoBiFunc() throws Exception {
         new Assertion<>(
             "Must convert function into bi-function",
             new BiFuncOf<>(
-                new FuncOf<>(input -> 1)
-            ).apply(1, 2),
-            new IsEqual<>(1)
+                new FuncOf<>(input -> input)
+            ),
+            new MatcherOf<>(
+                func -> {
+                    final Object first = new Object();
+                    final Object res = func.apply(first, "discarded");
+                    return res.equals(first);
+                }
+            )
         ).affirm();
     }
 
     @Test
     void convertsProcIntoBiFunc() throws Exception {
-        final AtomicBoolean done = new AtomicBoolean(false);
+        final AtomicReference<Object> done = new AtomicReference<>();
+        final Object result = new Object();
         new Assertion<>(
             "Must convert procedure into bi-function",
-            new BiFuncOf<String, Integer, Boolean>(
+            new BiFuncOf<>(
                 new ProcOf<>(
                     input -> {
-                        done.set(true);
+                        done.set(input);
                     }
                 ),
-                true
-            ).apply("hello world", 1),
-            new IsEqual<>(done.get())
+                result
+            ),
+            new MatcherOf<>(
+                func -> {
+                    final Object first = new Object();
+                    final Object res = func.apply(first, "discarded");
+                    return res.equals(result) && done.get().equals(first);
+                }
+            )
         ).affirm();
     }
 
     @Test
     void convertsScalarIntoBiFunc() throws Exception {
+        final Object obj = new Object();
         new Assertion<>(
             "Must convert scalar into bi-function",
-            new BiFuncOf<Boolean, Boolean, Boolean>(new True()).apply(false, false),
-            new IsTrue()
+            new BiFuncOf<>(new Constant<>(obj)).apply("discarded", "discarded"),
+            new IsSame<>(obj)
+        ).affirm();
+    }
+
+    @Test
+    void convertsLambdaIntoBiFunc() throws Exception {
+        new Assertion<>(
+            "Must convert lambda into bi-function",
+            new BiFuncOf<>((first, second) -> new Object[] {first, second}),
+            new MatcherOf<BiFunc<Object, Object, Object[]>>(
+                func -> {
+                    final Object first = new Object();
+                    final Object second = new Object();
+                    final Object[] res = func.apply(first, second);
+                    return res.length == 2 && res[0].equals(first) && res[1].equals(second);
+                }
+            )
         ).affirm();
     }
 }
diff --git a/src/test/java/org/cactoos/func/FuncOfTest.java b/src/test/java/org/cactoos/func/FuncOfTest.java
index 180668e320..78adff9e76 100644
--- a/src/test/java/org/cactoos/func/FuncOfTest.java
+++ b/src/test/java/org/cactoos/func/FuncOfTest.java
@@ -23,44 +23,70 @@
  */
 package org.cactoos.func;
 
-import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicReference;
 import org.cactoos.proc.ProcOf;
 import org.cactoos.scalar.Constant;
-import org.hamcrest.core.IsEqual;
 import org.junit.jupiter.api.Test;
 import org.llorllale.cactoos.matchers.Assertion;
+import org.llorllale.cactoos.matchers.MatcherOf;
 
 /**
  * Test case for {@link FuncOf}.
  *
  * @since 0.20
- * @checkstyle JavadocMethodCheck (500 lines)
  */
 final class FuncOfTest {
-
     @Test
     void convertsProcIntoFunc() throws Exception {
-        final AtomicBoolean done = new AtomicBoolean(false);
+        final AtomicReference<Object> done = new AtomicReference<>();
+        final Object result = new Object();
         new Assertion<>(
-            "Must convert procedure into function",
-            new FuncOf<String, Boolean>(
+            "Must convert Proc into Func",
+            new FuncOf<>(
                 new ProcOf<>(
                     input -> {
-                        done.set(true);
+                        done.set(input);
                     }
                 ),
-                true
-            ).apply("hello world"),
-            new IsEqual<>(done.get())
+                result
+            ),
+            new MatcherOf<>(
+                func -> {
+                    final Object input = new Object();
+                    final Object res = func.apply(input);
+                    return res.equals(result) && done.get().equals(input);
+                }
+            )
         ).affirm();
     }
 
     @Test
     void convertsScalarIntoFunc() throws Exception {
+        final Object result = new Object();
+        new Assertion<>(
+            "Must convert Scalar into Func",
+            new FuncOf<>(new Constant<>(result)),
+            new MatcherOf<>(
+                func -> {
+                    final Object res = func.apply("discarded");
+                    return res.equals(result);
+                }
+            )
+        ).affirm();
+    }
+
+    @Test
+    void convertsLambdaIntoFunc() throws Exception {
         new Assertion<>(
-            "Result of func must be equal to the original value",
-            new FuncOf<>(new Constant<>(1)).apply(new Object()),
-            new IsEqual<>(1)
+            "Must convert Lambda into Func",
+            new FuncOf<>(input -> input),
+            new MatcherOf<>(
+                func -> {
+                    final Object input = new Object();
+                    final Object res = func.apply(input);
+                    return res.equals(input);
+                }
+            )
         ).affirm();
     }
 }
diff --git a/src/test/java/org/cactoos/io/TempFolderTest.java b/src/test/java/org/cactoos/io/TempFolderTest.java
index c3be895f47..2aa8b43a9a 100644
--- a/src/test/java/org/cactoos/io/TempFolderTest.java
+++ b/src/test/java/org/cactoos/io/TempFolderTest.java
@@ -87,7 +87,6 @@ void deletesNonEmptyDirectory() throws Exception {
                                     filename,
                                     ""
                                 ).value();
-                                return true;
                             }
                         )
                     ).exec(
@@ -95,7 +94,6 @@ void deletesNonEmptyDirectory() throws Exception {
                             "file1.txt", "file2.txt", "file3.txt"
                         )
                     );
-                    return true;
                 }
             )
         ).exec(
@@ -129,7 +127,6 @@ void createDirectoryWithDirectoriesAndFiles() throws Exception {
                                     filename,
                                     ""
                                 ).value();
-                                return true;
                             }
                         )
                     ).exec(
@@ -137,7 +134,6 @@ void createDirectoryWithDirectoriesAndFiles() throws Exception {
                             "1.txt", "2.txt", "3.txt"
                         )
                     );
-                    return true;
                 }
             )
         ).exec(
diff --git a/src/test/java/org/cactoos/proc/ProcOfTest.java b/src/test/java/org/cactoos/proc/ProcOfTest.java
index ffd5bceadf..16dd560fdb 100644
--- a/src/test/java/org/cactoos/proc/ProcOfTest.java
+++ b/src/test/java/org/cactoos/proc/ProcOfTest.java
@@ -23,36 +23,58 @@
  */
 package org.cactoos.proc;
 
-import java.util.ArrayList;
-import java.util.List;
+import java.util.concurrent.atomic.AtomicReference;
 import org.cactoos.func.FuncOf;
 import org.junit.jupiter.api.Test;
 import org.llorllale.cactoos.matchers.Assertion;
-import org.llorllale.cactoos.matchers.HasValues;
+import org.llorllale.cactoos.matchers.MatcherOf;
 
 /**
  * Test case for {@link ProcOf}.
  *
  * @since 0.3
- * @checkstyle JavadocMethodCheck (500 lines)
  */
 final class ProcOfTest {
     @Test
     void worksWithFunc() throws Exception {
-        final String str = "test input";
-        final List<String> list = new ArrayList<>(1);
-        new ProcOf<String>(
-            new FuncOf<>(
-                input -> {
-                    list.add(input);
-                    return list.size();
+        final AtomicReference<Object> done = new AtomicReference<>();
+        new Assertion<>(
+            "Must execute Proc with Func",
+            new ProcOf<>(
+                new FuncOf<>(
+                    input -> {
+                        done.set(input);
+                        return true;
+                    }
+                )
+            ),
+            new MatcherOf<>(
+                proc -> {
+                    final Object input = new Object();
+                    proc.exec(input);
+                    return done.get() == input;
                 }
             )
-        ).exec(str);
+        ).affirm();
+    }
+
+    @Test
+    void worksWithLambda() throws Exception {
+        final AtomicReference<Object> done = new AtomicReference<>();
         new Assertion<>(
-            "Must contains the expected value from func",
-            list,
-            new HasValues<>(str)
+            "Must execute Proc with Lambda",
+            new ProcOf<>(
+                input -> {
+                    done.set(input);
+                }
+            ),
+            new MatcherOf<>(
+                proc -> {
+                    final Object input = new Object();
+                    proc.exec(input);
+                    return done.get() == input;
+                }
+            )
         ).affirm();
     }
 }
diff --git a/src/test/java/org/cactoos/proc/RunnableOfTest.java b/src/test/java/org/cactoos/proc/RunnableOfTest.java
index 38c5ddb0b6..9f5aa94cf7 100644
--- a/src/test/java/org/cactoos/proc/RunnableOfTest.java
+++ b/src/test/java/org/cactoos/proc/RunnableOfTest.java
@@ -23,7 +23,7 @@
  */
 package org.cactoos.proc;
 
-import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicReference;
 import org.cactoos.scalar.ScalarOf;
 import org.junit.jupiter.api.Test;
 import org.llorllale.cactoos.matchers.Assertion;
@@ -33,28 +33,27 @@
  * Test case for {@link RunnableOf}.
  *
  * @since 0.2
- * @checkstyle JavadocMethodCheck (500 lines)
  */
-@SuppressWarnings("PMD.AvoidDuplicateLiterals")
 final class RunnableOfTest {
 
     @Test
     void convertsProcIntoRunnable() {
-        final AtomicBoolean done = new AtomicBoolean();
+        final AtomicReference<Object> done = new AtomicReference<>();
+        final Object obj = new Object();
         new Assertion<>(
             "Must execute Runnable with Proc",
             new RunnableOf(
                 new ProcOf<>(
-                    ignored -> {
-                        done.set(true);
+                    input -> {
+                        done.set(input);
                     }
                 ),
-                "ignored"
+                obj
             ),
-            new MatcherOf<Runnable>(
-                input -> {
-                    input.run();
-                    return done.get();
+            new MatcherOf<>(
+                runnable -> {
+                    runnable.run();
+                    return done.get().equals(obj);
                 }
             )
         ).affirm();
@@ -62,21 +61,42 @@ void convertsProcIntoRunnable() {
 
     @Test
     void convertsScalarIntoRunnable() {
-        final AtomicBoolean done = new AtomicBoolean();
+        final AtomicReference<Object> done = new AtomicReference<>();
+        final Object obj = new Object();
         new Assertion<>(
             "Must execute Runnable with Scalar",
             new RunnableOf(
                 new ScalarOf<>(
                     () -> {
-                        done.set(true);
-                        return null;
+                        done.set(obj);
+                        return "discarded";
                     }
                 )
             ),
+            new MatcherOf<>(
+                runnable -> {
+                    runnable.run();
+                    return done.get().equals(obj);
+                }
+            )
+        ).affirm();
+    }
+
+    @Test
+    void convertsLambdaIntoRunnable() {
+        final AtomicReference<Object> done = new AtomicReference<>();
+        final Object obj = new Object();
+        new Assertion<>(
+            "Must execute Runnable with Lambda",
+            new RunnableOf(
+                () -> {
+                    done.set(obj);
+                }
+            ),
             new MatcherOf<Runnable>(
-                input -> {
-                    input.run();
-                    return done.get();
+                runnable -> {
+                    runnable.run();
+                    return done.get().equals(obj);
                 }
             )
         ).affirm();
diff --git a/src/test/java/org/cactoos/scalar/AndInThreadsTest.java b/src/test/java/org/cactoos/scalar/AndInThreadsTest.java
index c4eddfed23..decc2ae9bb 100644
--- a/src/test/java/org/cactoos/scalar/AndInThreadsTest.java
+++ b/src/test/java/org/cactoos/scalar/AndInThreadsTest.java
@@ -23,7 +23,6 @@
  */
 package org.cactoos.scalar;
 
-import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
@@ -94,9 +93,9 @@ void allFalse() throws Exception {
     }
 
     @Test
-    void emptyIterator() throws Exception {
+    void emptyIterable() throws Exception {
         new Assertion<>(
-            "Iterator must be empty",
+            "Must iterate over empty iterable",
             new AndInThreads(new IterableOf<Scalar<Boolean>>()),
             new ScalarHasValue<>(true)
         ).affirm();
@@ -106,10 +105,10 @@ void emptyIterator() throws Exception {
     void iteratesList() {
         final List<String> list = new Synced<>(new ListOf<>());
         new Assertion<>(
-            "Must iterate a list with a procedure",
+            "Must iterate a list with a function",
             new AndInThreads(
                 new Mapped<>(
-                    new FuncOf<String, Scalar<Boolean>>(list::add, () -> true),
+                    new FuncOf<String, Scalar<Boolean>>(list::add, new True()),
                     new IterableOf<>("hello", "world")
                 )
             ),
@@ -135,32 +134,6 @@ void iteratesList() {
         ).affirm();
     }
 
-    @Test
-    void iteratesEmptyList() {
-        final List<String> list = new Synced<>(
-            new ArrayList<>(2)
-        );
-        new Assertion<>(
-            "Must iterate an empty list",
-            new AndInThreads(
-                new Mapped<>(
-                    new FuncOf<String, Scalar<Boolean>>(list::add, () -> true),
-                    new IterableOf<String>()
-                )
-            ),
-            new ScalarHasValue<>(
-                Matchers.allOf(
-                    Matchers.equalTo(true),
-                    new MatcherOf<>(
-                        value -> {
-                            return list.isEmpty();
-                        }
-                    )
-                )
-            )
-        ).affirm();
-    }
-
     @Test
     void worksWithFunc() throws Exception {
         MatcherAssert.assertThat(
diff --git a/src/test/java/org/cactoos/scalar/RepeatedTest.java b/src/test/java/org/cactoos/scalar/RepeatedTest.java
index 89f11250c5..6c335a0e36 100644
--- a/src/test/java/org/cactoos/scalar/RepeatedTest.java
+++ b/src/test/java/org/cactoos/scalar/RepeatedTest.java
@@ -61,7 +61,7 @@ void throwsIfZero() {
                     () -> {
                         throw new IllegalStateException("intended to fail");
                     },
-                    true
+                    "discarded"
                 ),
                 0
             ).value(),
diff --git a/src/test/java/org/cactoos/scalar/ScalarOfTest.java b/src/test/java/org/cactoos/scalar/ScalarOfTest.java
index 86750db836..1a19164fbe 100644
--- a/src/test/java/org/cactoos/scalar/ScalarOfTest.java
+++ b/src/test/java/org/cactoos/scalar/ScalarOfTest.java
@@ -23,11 +23,13 @@
  */
 package org.cactoos.scalar;
 
+import java.util.concurrent.atomic.AtomicReference;
 import org.cactoos.func.FuncOf;
 import org.cactoos.proc.ProcOf;
 import org.cactoos.proc.RunnableOf;
 import org.junit.jupiter.api.Test;
 import org.llorllale.cactoos.matchers.Assertion;
+import org.llorllale.cactoos.matchers.MatcherOf;
 import org.llorllale.cactoos.matchers.ScalarHasValue;
 
 /**
@@ -42,7 +44,7 @@ final class ScalarOfTest {
     void worksWithCallable() {
         final Object obj = new Object();
         new Assertion<>(
-            "must hold the same value as given by callable",
+            "Must convert Callable into Scalar",
             new ScalarOf<>(new CallableOf<>(new Constant<>(obj))),
             new ScalarHasValue<>(obj)
         ).affirm();
@@ -51,29 +53,68 @@ void worksWithCallable() {
     @Test
     void worksWithRunnable() {
         final Object obj = new Object();
+        final Object result = new Object();
+        final AtomicReference<Object> done = new AtomicReference<>();
         new Assertion<>(
-            "must hold the same value as given",
-            new ScalarOf<>(new RunnableOf(ignored -> { }, "ignored"), obj),
-            new ScalarHasValue<>(obj)
+            "Must convert Runnable into Scalar",
+            new ScalarOf<>(
+                new RunnableOf(
+                    () -> {
+                        done.set(result);
+                    }
+                ),
+                obj
+            ),
+            new MatcherOf<>(
+                scalar -> {
+                    final Object res = scalar.value();
+                    return res.equals(obj) && done.get().equals(result);
+                }
+            )
         ).affirm();
     }
 
     @Test
     void worksWithFunc() {
-        final Object obj = new Object();
+        final Object ipt = new Object();
         new Assertion<>(
-            "must hold the same value as given by func",
-            new ScalarOf<>(new FuncOf<>(new Constant<>(obj)), "ignored"),
-            new ScalarHasValue<>(obj)
+            "Must convert Func into Scalar",
+            new ScalarOf<>(new FuncOf<>(input -> input), ipt),
+            new ScalarHasValue<>(ipt)
         ).affirm();
     }
 
     @Test
     void worksWithProc() {
+        final Object ipt = new Object();
+        final Object result = new Object();
+        final AtomicReference<Object> done = new AtomicReference<>();
+        new Assertion<>(
+            "Must convert Proc into Scalar",
+            new ScalarOf<>(
+                new ProcOf<>(
+                    input -> {
+                        done.set(input);
+                    }
+                ),
+                ipt,
+                result
+            ),
+            new MatcherOf<>(
+                scalar -> {
+                    final Object res = scalar.value();
+                    return res.equals(result) && done.get().equals(ipt);
+                }
+            )
+        ).affirm();
+    }
+
+    @Test
+    void worksWithLambda() {
         final Object obj = new Object();
         new Assertion<>(
-            "must hold the expected value",
-            new ScalarOf<>(new ProcOf<>(ignored -> { }), "ignored", obj),
+            "Must convert Lambda into Scalar",
+            new ScalarOf<>(() -> obj),
             new ScalarHasValue<>(obj)
         ).affirm();
     }