fix(core) tests fixes

Author: robotomize

src/Regression/ExponentialRegression.php

@@ -55,7 +55,7 @@ public function calculate()
             $this->resultSequence[] = $coordinate;
         }
 
-        $this->equation = 'y = ' . \round($A, 2) . '+ e^(' . \round($B, 2) . 'x)';
+        $this->equation = 'y = ' . \round($A, 2) . ' + e^(' . \round($B, 2) . 'x)';
 
         $this->push();
     }

src/Regression/PowerRegression.php

@@ -54,7 +54,7 @@ public function calculate()
             $this->resultSequence[] = $coordinate;
         }
 
-        $this->equation = 'y = ' . \round($A, 2) . '* x^' . \round($B, 2);
+        $this->equation = 'y = ' . \round($A, 2) . ' * x^' . \round($B, 2);
 
         $this->push();
     }

tests/ExponentialRegressionTest.php

@@ -57,13 +57,13 @@ public function testCalculate()
         /** @var RegressionModel $regressionModel */
         $regressionModel = $linear->getRegressionModel();
 
-        $this->assertEquals('y = 30.2+ e^(0.39x)', $regressionModel->getEquation());
+        $this->assertEquals('y = 30.2 + e^(0.39x)', $regressionModel->getEquation());
         $this->assertEquals(1470, \round($regressionModel->getResultSequence()[9][1]));
         $this->assertEquals(997, \round($regressionModel->getResultSequence()[8][1]));
         $this->assertEquals(676, \round($regressionModel->getResultSequence()[7][1]));
 
         $regressionModel = RegressionFactory::exponential($this->rows[1]);
-        $this->assertEquals('y = 12.36+ e^(0.02x)', $regressionModel->getEquation());
+        $this->assertEquals('y = 12.36 + e^(0.02x)', $regressionModel->getEquation());
         $this->assertEquals(13, \round($regressionModel->getResultSequence()[0][1]));
         $this->assertEquals(13, \round($regressionModel->getResultSequence()[1][1]));
         $this->assertEquals(13, \round($regressionModel->getResultSequence()[2][1]));

tests/LogarithmicRegressionTest.php

@@ -57,13 +57,13 @@ public function testCalculate()
         /** @var RegressionModel $regressionModel */
         $regressionModel = $linear->getRegressionModel();
 
-        $this->assertEquals('y = -320.03 + 504.51ln(x)', $regressionModel->getEquation());
+        $this->assertEquals('y = -320.03 + 504.51 ln(x)', $regressionModel->getEquation());
         $this->assertEquals(842, \round($regressionModel->getResultSequence()[9][1]));
         $this->assertEquals(788, \round($regressionModel->getResultSequence()[8][1]));
         $this->assertEquals(729, \round($regressionModel->getResultSequence()[7][1]));
 
         $regressionModel = RegressionFactory::logarithmic($this->rows[1]);
-        $this->assertEquals('y = 11.73 + 1.43ln(x)', $regressionModel->getEquation());
+        $this->assertEquals('y = 11.73 + 1.43 ln(x)', $regressionModel->getEquation());
         $this->assertEquals(12, \round($regressionModel->getResultSequence()[0][1]));
         $this->assertEquals(13, \round($regressionModel->getResultSequence()[1][1]));
         $this->assertEquals(13, \round($regressionModel->getResultSequence()[2][1]));