diff --git a/.github/workflows/maven.yml b/.github/workflows/maven.yml
index 6a3a6ba6..adc21f57 100644
--- a/.github/workflows/maven.yml
+++ b/.github/workflows/maven.yml
@@ -10,43 +10,42 @@ name: Java CI with Maven
 
 on:
   push:
-    branches: [ "main","development" ]
+    branches: ["main", "development"]
   pull_request:
-    branches: [ "main","development" ]
+    branches: ["main", "development"]
 
 jobs:
   build:
-
     runs-on: ubuntu-latest
-    
+
     steps:
-    - uses: actions/checkout@v3
-    - name: Set up JDK 20.0.2
-      uses: actions/setup-java@v3
-      with:
-        java-version: '20.0.2'
-        distribution: 'temurin'
-        cache: maven
-        
-    - name: Set up Environment Variables
-      env:
-        URL: ${{ secrets.URL }}
-        USER_NAME: ${{ secrets.USER_NAME }}
-        PASSWORD: ${{ secrets.PASSWORD }}
-        ACCESS_KEY: ${{ secrets.ACCESS_KEY }}
-        SECRET_KEY: ${{ secrets.SECRET_KEY }}
-        URL_TEST: ${{ secrets.URL_TEST }}
-        USER_NAME_TEST: ${{ secrets.USER_NAME_TEST }}
-        PASSWORD_TEST: ${{ secrets.PASSWORD_TEST }}
-      run: |
-        echo "URL=$URL" > $GITHUB_WORKSPACE/.env
-        echo "USER_NAME=$USER_NAME" >> $GITHUB_WORKSPACE/.env
-        echo "PASSWORD=$PASSWORD" >> $GITHUB_WORKSPACE/.env
-        echo "ACCESS_KEY=$ACCESS_KEY" >> $GITHUB_WORKSPACE/.env
-        echo "SECRET_KEY=$SECRET_KEY" >> $GITHUB_WORKSPACE/.env
-        echo "URL_TEST=$URL_TEST" >> $GITHUB_WORKSPACE/.env
-        echo "USER_NAME_TEST=$USER_NAME_TEST" >> $GITHUB_WORKSPACE/.env
-        echo "PASSWORD_TEST=$PASSWORD_TEST" >> $GITHUB_WORKSPACE/.env
-        
-    - name: Build with Maven
-      run: mvn -B package --file pom.xml
\ No newline at end of file
+      - uses: actions/checkout@v3
+      - name: Set up JDK 20.0.2
+        uses: actions/setup-java@v3
+        with:
+          java-version: "20.0.2"
+          distribution: "temurin"
+          cache: maven
+
+      - name: Set up Environment Variables
+        env:
+          URL: ${{ secrets.URL }}
+          USER_NAME: ${{ secrets.USER_NAME }}
+          PASSWORD: ${{ secrets.PASSWORD }}
+          ACCESS_KEY: ${{ secrets.ACCESS_KEY }}
+          SECRET_KEY: ${{ secrets.SECRET_KEY }}
+          URL_TEST: ${{ secrets.URL_TEST }}
+          USER_NAME_TEST: ${{ secrets.USER_NAME_TEST }}
+          PASSWORD_TEST: ${{ secrets.PASSWORD_TEST }}
+        run: |
+          echo "URL=$URL" > $GITHUB_WORKSPACE/.env
+          echo "USER_NAME=$USER_NAME" >> $GITHUB_WORKSPACE/.env
+          echo "PASSWORD=$PASSWORD" >> $GITHUB_WORKSPACE/.env
+          echo "ACCESS_KEY=$ACCESS_KEY" >> $GITHUB_WORKSPACE/.env
+          echo "SECRET_KEY=$SECRET_KEY" >> $GITHUB_WORKSPACE/.env
+          echo "URL_TEST=$URL_TEST" >> $GITHUB_WORKSPACE/.env
+          echo "USER_NAME_TEST=$USER_NAME_TEST" >> $GITHUB_WORKSPACE/.env
+          echo "PASSWORD_TEST=$PASSWORD_TEST" >> $GITHUB_WORKSPACE/.env
+
+      - name: Build with Maven
+        run: mvn -B package --file pom.xml
diff --git a/src/main/java/com/casaculturaqxd/sgec/jdbc/DatabasePostgres.java b/src/main/java/com/casaculturaqxd/sgec/jdbc/DatabasePostgres.java
index 1763cffe..5ebf5512 100644
--- a/src/main/java/com/casaculturaqxd/sgec/jdbc/DatabasePostgres.java
+++ b/src/main/java/com/casaculturaqxd/sgec/jdbc/DatabasePostgres.java
@@ -86,7 +86,7 @@ public void setSenha(String passwordKey) throws IncorrectEnvironmentVariableExce
     }
 
     private boolean variavelEnvExists(String envKey) {
-        return dotenv.get(envKey) == null;
+        return dotenv.get(envKey) != null;
     }
 
 }
diff --git a/src/test/java/com/casaculturaqxd/sgec/jdbc/TestDatabasePostgres.java b/src/test/java/com/casaculturaqxd/sgec/jdbc/TestDatabasePostgres.java
new file mode 100644
index 00000000..ce82dfb7
--- /dev/null
+++ b/src/test/java/com/casaculturaqxd/sgec/jdbc/TestDatabasePostgres.java
@@ -0,0 +1,62 @@
+package com.casaculturaqxd.sgec.jdbc;
+
+import java.sql.Connection;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+
+
+public class TestDatabasePostgres {
+    DatabasePostgres database;
+    String INVALID_ENV = "";
+
+    public TestDatabasePostgres() {
+        database = DatabasePostgres.getInstance("URL_TEST", "USER_NAME_TEST", "PASSWORD_TEST");
+        INVALID_ENV = "";
+    }
+
+    @BeforeEach
+    public void setUp() throws IncorrectEnvironmentVariableException {
+        database = DatabasePostgres.getInstance("URL_TEST", "USER_NAME_TEST", "PASSWORD_TEST");
+    }
+
+
+    @Test
+    public void testUniqueInstance() {
+        Connection firstConnection = database.getConnection();
+        Connection secondConnection = database.getConnection();
+        assertEquals(firstConnection, secondConnection);
+    }
+
+
+    @Test
+    public void testDesconectarOnValidConnection() {
+        database.getConnection();
+        assertDoesNotThrow(() -> {
+            database.desconectar(database.getConnection());
+        });
+    }
+
+    @Test
+    public void testSetInvalidUrlDataBase() throws IncorrectEnvironmentVariableException {
+        assertThrows(IncorrectEnvironmentVariableException.class, () -> {
+            database.setUrlDataBase(INVALID_ENV);
+        });
+    }
+
+    @Test
+    public void testSetInvalidNomeUsuario() {
+        assertThrows(IncorrectEnvironmentVariableException.class, () -> {
+            database.setNomeUsuario(INVALID_ENV);
+        });
+    }
+
+    @Test
+    public void testSetInvalidSenha() {
+        assertThrows(IncorrectEnvironmentVariableException.class, () -> {
+            database.setSenha(INVALID_ENV);
+        });
+    }
+
+}